R. H. Gibbs, Jr.
The Females of Enallagma laterale Morse and recurvatum Davis (Odonata: Coenagrionidae).
Psyche 62(1):10-18, 1955.

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THE FEMALES OF ENALLAGMA LATERALE MORSE
AND RECURVATUM DAVIS
(ODONATA : COENAGRIONIDAE)
Department of Conservation
Cornell University, Ithaca, New York
Of the 23 northeastern members of the genus Enallagma, the females of piscinarium, laterale, and recurvaturn have not been described. E. piscinarium is apparently known only from the type male. Although males of laterale have been taken in several localities, the female remains un- recorded. The female of recurvatum may have been col- lected, but references to it are quite misleading. In the
original description of the species by Davis (1913) the female is supposedly described, but the description is quite inadequate and not diagnostic. Byers, in his key (l927), does not distinguish it from E. hageni other than by its comparative rarity. Garman (1927) stated that "all sup- posed females thus far examined have proved to belong to other species."
Systematic collecting on Cape Cod, Massachusetts, has resulted in the finding of tandem pairs of both laterale and recurvaturn. In addition, Thomas W. Donnelly has al- lowed me to examine some collections sent to him by Mr. Roy Latham from Riverhead, Long Island, New York, which contained two females of recurvaturn and one of laterale. The following descriptions are based on these Cape Cod and Long Island specimens.
For suggestions during the preparation of this manu- script, I wish to express appreciation to E. M. Walker, L.
K. Gloyd, M. J. Westfall, Jr., T. W. Donnelly, H. E. Evans, and J. G. Franclemont.
Enallagma laterale Morse. Female
Psyche 7: 274. 1895
Color: Olivaceous, washed with light blue, and black. Head: Dorsum black; pale frontal margin reaching bases Psiche 62:10.18 ( 1955). hup Ytpsycht enlclub orgt62'62-010 html



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19551 Gibbs - Females of Enallagma 11
of antennae ; postocular spots elongate, comma-shaped, connected by a narrow, pale occipital bar, not quite reach- ing the ocular margins; face pale except postclypeus black with pale margins; mouthparts and rear of head pale; antennae black, apices of first and second segments pale. Prothorax: Front lobe pale bordered with black; middle lobe black dorsally, pale laterally, a dorsolateral pale spot present on each side and variable in size, a pair of prom- inent dorsolateral pits present near the caudal margin'; hind lobe black with pale lateral margins, caudal margin convex and entire.
Pterothorax: Pale with black middorsal stripe occupying about half the mesepisternum and slightly narrowed pos- teriorly ; black humeral stripe slightly narrower than pale antehumeral stripe, of about constant width throughout, but with a slight widening- posterior to the mesinfraepis- ternum; first lateral stripe represented by a mere posterior vestige; metapleural suture covered by a thin second lat- eral stripe, which expands posteriorly into a spot; humeral and middorsal stripes connected posteriorly by the black of the antealar carina and sinus, which fades slightly laterad of the humeral stripe. Coxae and trochanters en- tirely pale. Femora and tibiae pale, each with a black external stripe for almost the entire length; tarsi pale, each with distal end of third segment dark; spines of legs black; claws pale with black tips.
Mesostigmal laminae: Widest in mesal half; a closed mesal concavity present, deepest posteriorly ; the entire lateral half twisted and upturned at an angle of 60 degrees or more; most of lateral half pale; separated from the thoracic depression by a posterior groove for its lateral half only.
Wings: Venation black or dark brown; pterostigma light brown. Ms arises between the 4th and 5th postnodal cross- veins in the front wings, between the 3rd and 4th in the hind wings; postnodals 9-12 in front wings, 8-10 in hind wings; Mia arises at about the level of the 8th postnodal in both wings.
Abdomen: Pale with black as follows: Segment one, a squared middorsal spot on basal half, a small apical spot



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12 Psyche [March
on each side; segment 2, entire dorsum, widened slightly toward apex, connected to a narrow apical ring-; segments 3-7, entire dorsum, abruptly constricted basally, slightly widened anteapically, connected with a narrow apical ring"; segment 8, entire dorsum, widened gradually from base to apex; segments 9 and 10, entire dorsum. Midventral
sternal carinae black on 1-8,
Anal appendages and valves
and styli of ovipositor pale; apex of each valve of ovi- poaitor, to base of stylus, extends not quite to apex of seg- ment 10 excluding appendages.
Ventral spine of segment
8 black to dark brown, sharp.
Figure 1. Left mesostigma1 lamina of EnaUagma females in doma- lateral aspect. A. laterale. B. recwvatwa. C. daulsi. D. mtn~ciAtm. ca. 35x.
Measurements: Total length to apex of segment 10, ex- cluding appendages ; 24.8-28.0 mm. ; length of abdomen : 20.0-22.7 mm. ; length of front wing : 14.5-17.8 mm, ; length of hind wing-: 15.4-16.3 mm. The two Cape Cod speci- mens are larger; the Long Island specimen is represented by the smaller extreme in each case.
Described from two specimens captured in tandem with males by the writer at Jabinette's Pond, West Yarmouth, Massachusetts, on June 13, 1953, and one specimen from Riverhead, Long Island, New York, caught on May 29, 1953, by Mr. Roy Latham.
Enallagmu rematurn Davis. Female
Jour. N. Y. Ent. Soc. 21: 15-16. 1913
Color: Olivaceous, washed with light blue, and black.



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19551 Gibbs- Females of Enallagm 13
Head: Dorsum black; pale frontal margin not quite reaching bases of antennae; postocular spots comma- shaped, isolated from the light occipital carina, not quite reaching ocular margins; face pale except postclypeus black and pale lateral edges; mouthparts and rear of head pale; antennae black, apices of first and second seg- ments pale.
Prothorax: Front lobe pale bordered with black; middle lobe black dorsally, pale laterally, a dorsolateral pale spot either present on each side and variable in size, or absent, and a pair of prominent dorsolateral pits present near the caudal margin; hind lobe black with pale lateral mar- gins, caudal margin convex and entire.
Pterothorax: Pale with black middorsal stripe occupying slightly more than half the mesepisternum, somewhat narrowed posteri'orly; humeral black stripe slightly wider than the pale antehumeral stripe, widened at the mesin- fraepisternal suture, narrower on the mesinfraepisternum ; first lateral stripe absent or a mere vestige; second lateral stripe a fine line on the metapleural suture, widened pos- teriorly into a spot; middorsal and humeral stripes con- nected posteriorly by the black of the antealar earina and sinus, which continues laterad to the region of the first lateral stripe. Coxae and trochanters entirely pale. Femora
and tibiae pale, each with a wide black lateral stripe cov- ering most of their lateral surface; tarsi pale, each with tip of third segment dark; spines of legs black; claws pale with black tips.
Mesostigmal laminae: Mesa1 edge at about a 30 degree angle to middorsal carina; mesal half much wider than lateral half ; postero-mesa1 corner much thickened ; a deep depression near mesal margin ; anterior margin of lateral portion upturned; lateral end with a variable, usually small, light spot.
Wings: Venation black or dark brown; pterostigma light brown. Ma arises between the 4th and 5th or 5th and 6th postnodal crossveins in the front wings, between the 3rd and 4th or 4th and 5th in hind wings; postnodals 9-11 in front wings, 8-10 in hind wings, the majority having



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14 Psyche [March
11 and 9; Mia arises at about the level of the 7th to 9th postnodal crossvein in the front wings, about the 7th or 8th in the hind wings, the majority arising at the 8th in both wings.
Abdomen: Pale with black as follows: Segment one, a middorsal basal spot and a lateral apical transverse dash ; segment 2, entire dorsum, constricted or narrower in an- terior half, connected with an apical ring; segments 3-7, en- tire dorsum, abruptly constricted basally, slightly widened anteapically, connected with an apical ring; segment 8, a narrow middorsal line abruptly widened to cover apical dolrsum; segments 9 and 10, entire dorsum. Midventral sternal carinae black on 1-8.
Anal appendages and valves
and styli of ovipositor pale; apex of each valve of ovi-
positor, to base of stylus, extends not quite to apex of segment 10 excluding appendages. Ventral spine of seg- ment 8 black or dark brown, sharp.
Measurements: Total length to apex of segment 10, ex- clusive of appendages : 26.8-28.2 mm. ; length of abdomen : 21.0-22.2 mm. ; length of front wing: 16.1-18.0 mm. ; length of hind wing". 14.7-16.9 mm. Taken from four Cape Cod specimens and one from Long Island. The Long Island specimen is represented in each measurement by the smal- ler extreme.
Described from 11 specimens from the following lo- calities: Flax Pond, North Falmouth, Mass., June 17, 1951 (3), June 16, 1953 (5), and Jabinette's Pond, West Yar- mouth, Mass., June 13, 1953 (I), all collected by the writer; and Riverhead, Long Island, New York, May 29, 1953 (I), June 2, 1953 (I), collected by Mr. Roy Latham. Key to Females of Ten Species of Enallagma, Based Principally on Mesostigmal Laminae In the key which follows, the females of ten species of Enallagma are compared. These ten comprise those which might be confused for one reason or another, or which may be closely related to laterale or recurvatzm. Relation- ships among the species of Enallagma are difficult to de- termine and, to date, have been largely based on the form



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19551 Gibbs - Females of Enallagma 15
of the anal appendages of the male. It has been almost impossible to divide the females into logical groups. Men- tion of the males of the species being compared, then, may make clearer the reason for comparing their females. Enallagma laterale would appear, from gross examina- tion of the male genitalia, to be close to E. piscimrium, E. davisi, and E. boreale) and perhaps to E. minmculum (Westfall, 1943). In these species the superior anal ap- pendage is shorter than segment 10 and ranges from bluntly rounded to deeply, but narrowly, cleft. E. minus- culum is most like davisi, but the lower arm of the superior anal appendage of the former appears prominently circular in lateral view.
The male of E. recurvatum bears a superficial resem- blance to E. vernale, but the latter species is believed by Mrs. Gloyd (1943) and by Walker (1953) to be more closely related to cyathigerum. The recurved superior anal appendages of recurvatum are somewhat similar to those of E. hageni, which, however, are straight as viewed later- ally. Both laterale and davisi males are characterized by a lateral black mark on the eighth abdominal segment. Several recurvatum from Cape Cod also show this mark, although it is not commonly present.
The caudal lamellae of the nymphs of E. ebrium and E. geminatum resemble those of laterale (Howe, 1921), in- dicating possible relationship. The nymph of recurvatum is unknown, and that of laterale has never been adequately described.
The form of the mesostigmal laminae may prove to be indicative of relationships among the females of Enal- lagma. At any rate, the laminae are by far the best means for identifying the species. If Byers (1927) had pos- sessed females of both hageni and recurvatum, he could have recognized them both immediately by a glance at the laminae. In the key this character will play a prom- inent part. For illustrations of the mesostigmal laminae of most of the keyed species, I recommend the beautiful plates in Walker (1953). Those of laterale, recurvatum, and davisi (from the allotype) are figured in the present paper, along with that of minusculum. The latter is in-



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16 Psyche
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eluded because Walker's illustration is somewhat decep- tive. The resemblance is obvious, but I have found the lateral ends bluntly pointed, not rounded, and the diagonal ridge which runs antero-laterally from the postero-mesa1 region is diagnostic.
...................
1 - Lamina more than half as wide as long.. ..2
- Lamina less than half as wide as long. .................... 3 2 (1) Lamina widest mesally, gradually narrowing laterally f,o,r two-thirds of length, rapidly narrowing in lateral one-third to form an antero-lateral blunt point, pos- tero-lateral edge not curled upward; dorsum of ab- dominal segment one entirely black, connected to an .............................................................. apical ring.. ebrium
Lamina widest about midway to lateral end, the pos- ter,~#-lateral edge curled upward, often extremely so, a blunt point f orrned antero-laterally ; dorsum of seg- ment one with a black basal spot and an apical spot ........................................................... on each side hageni
3(1) Lamina with a mesa1 enclosed concavity formed by the high antero-mesa1 corner and the raised or thick- ened postero-mesa1 edge. ........................................... .4 - N,o such concavity present; edges may be curled to florm a shallow basin or cavity may be formed by anterior corner and be open posteriorly ................... 8 4(3) Postero-mesa1 margin of lamina tilted ............ vemate - Postero-mesa1 margin of lamina not tilted, but may be thickened ................................................................. .5 5 (4) Lam,ina twisted so that entire lateral half is greatly tilted ............................................................................. .6 Entire lateral half of lamina not up tilted; antero- lateral margin may be raised .................................... ..7 6 (5) Twisted lateral portion of lamina bent posteriorly ; lamina well-demarcated from thorax by a posterior groove for its entire length ; prothoracic pits ab- sent; segment one with domum entirely black, con- nected to apical ring; black of segment 8 not nar- rowed; black of segments 9 and 10 extending far later ad .......................................................... rnimisczdum



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19551 Gibbs - Females of Enallagma 17
- Twisted lateral portion of lamina not bent posterior- ly ; lamina definitely demarcated only in lateral half ; prothoracic pits present; segment one with a black basal spot, lateral apical spots; segment 8 with black slightly narr,owed anteriorly; black of segments 9 and 10 not extending much beyond a mid-lateral .................................................................... point lat erale
7(5) Mesal edge of lamina at about 30 degree angle to mid-dor,sal carina ; postero-mesa1 corner much more thickened than antero-mesal, posterior edge broadly curved in mesal half, mesal half much broader than lateral half; pit in frame rather wide;
prothoracic
pits present; black of segment 8 constricted in basal half, no lateral stripe present on 2 or 8.. ... .recurvaturn - Mesal edge of lamina nearly parallel to mid-dorsal carina ; antero-mesa1 corner more thickened than pos- tero-mesal, posterior edge nearly straight, mesal half not greatly broader than lateral half; pit in frame rather small ; protho,racic pits absent
(sometimes a
deceptive set of shallow areas present) ; a lateral black stripe present on segment 2; black of segment 8 narrow dorsa.lly, a black lateral stripe present, the two black porti,ons enclosing a blue spot on each .............................................................. side geminaturn
8 (3) Lamina nearly flat except tilted antero-lateral margin ; ...................................
prothoracic pits present.. .davisi
-Lamina not flat; anteri,or open concavity present; ................................................ prothoracic pits absent,. 9
9 (8) Mesal edge of lamina at about a 30 degree angle to mid-dorsal carinla ; postero-mesa1 margin sharply de- limited from the thorax by a groove.. ....... .cyathigerum - Mesal edge of lamina nearly pa,rallel to mid-dorsal carina ; postero-mesa1 margin not clearly demarcated from thorax ...................................................... b oreale



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LITERATURE CITED
BYERS, C. FRANCIS
1927. Key to the North American species of Enallagma with a description of a new species. Trans. Am. Ent. Soc. 53: 249-260. DAVIS, WILLIAM T.
1913. Dragonflies of the vicinity of New York City with a descrip- tion of a new species. Jour. N. Y. Ent. Soc. 21: 11-29. GARMAN, PHILIP
1927.
Guide to the insects of Connecticut. Part V. The Odonata or dragonflies of Connecticut. State Geol. and Nat. Hist. Surv. Bull. 39. Pp. 331.
GLOYD, LEONORA K.
1943. Enallagma vernale, a new species of Odonata from Michigan. Occ. Pap. Mus. Zool. Univ. Mich. 479: 1-8. HOWE, R. HEBER, JR.
1921. Manual of the Odonata of New England. Nymphs. Mem. Thoreau Mus. Nat. Hist. 11: 103-115.
MORSE, ALBERT P.
1895. New North American Odonata. 11. Psyche 7: 274-275. WALKER, EDMUND M.
1953. The Odonata of Canada and Alaska. Vol. I. Pp. xi 4-292. Univ. Toronto Press.
WESTFALL, MINTER J., JR.
1943. Enallagma davisi, a new species from Florida. Ent, News 54: 103-108.




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