250 Benj. D. Walsh on the Insects inhabiting the Galls 



this genus with the obsolescence of the 3rd submarginal cell % 9 , is 

 as inexplicable a thing as wby blue eyes in the domestic cat should be 

 invariably correlated with deafness. (Darwin, On'g. Spec. p. 18.) 

 Judging from what Brulle says, (Hymen, p. 666,) Pteronus Jurine 

 must be synonymous with Euura Newman ; although Westwood (#y- 

 nops. p. 54.) gives Pteronus Jur. as the synonym of Loplujrus Latr., 

 which last has multiarticulate, not 9-jointed antennae, and also of Gla- 

 </ius Leach, which has % antennae pectinated. But be this as it may, 

 it is always better to retain a name that is in general use, than to rake 

 up an old name that was used by our grandfathers. "The naturalist," 

 says Dr. P. P. Carpenter, "is not necessarily an archaeologist." 



Genus EUURA. — Gall-makers. 



No. 16. Gall Salicis gemma, n. sp. — On Salix humilis. The lateral bud of a 

 twig, enlarged so as to be twice or thrice as long wide and thick as the natural 

 bud before it begins to expand in the spring, its external surface otherwise en- 

 tirely unchanged both in texture and color. Internally, instead of the normal 

 downy embryo leaves, it contains early in the autumn a homogeneous, grass- 

 green, fleshy matter, which is afterwards gradually consumed by the larva, 

 leaving nothing at last but a mere shell, as thin as paper, and partly filled with 

 excrement. Sometimes, from the egg failing to hatch out, this green fleshy 

 matter remains unaltered till the spring. The gall is monothalamous, sometimes 

 one only on a twig, sometimes two or three or more at irregular intervals, very 

 rarely as many as 3 or 4 formed out of 3 or 4 consecutive buds. Common and 

 not local. Described from 34 specimens. Length .17 — .36 inch; breadth .10 — 

 .17 inch. Analogous to the Cecidomyidous gall 8. cornu Walsh, but very differ- 

 ent in its general aj^earance and in its internal structure. 



Larva. The larva is 20-footed, and on Oct. 2 is .13 — .19 inch long, of a green- 

 ish-white color, the head tinged with dusky, and with the usual fuscous eye- 

 spots. Mouth dusky. At this date a few galls were already bored, and the other 

 larvse not long after this bored out, and retired an inch or so underground, 

 where they spin a thin, whitish, silken cocoon, to which many particles of 

 earth adhere externally. Two specimens. 



Pupa unknown. 



Imago. Euura s. gemma, n. sp. — 9 Shining black. Head pale luteous: eyes, 

 ;i square spot enclosing the ocelli, and separated by a moderately wide orbit 

 from the eyes, and also the tips of the mandibles, all black. Clypeus emarginate 

 in a circular arc of about 90°. Palpi fuscous at tip. Occiput clouded in the 

 middle with black. Labrum rounded at tip. Antennae black, except their ex- 

 treme tips below which are dull rufous, three-fifths as long as the body, joints 

 3 — 5 subequal, 4 slightly the longest, 5 — 9 very slowly shorter and shorter. Tho- 

 rax with the tegulre and the upper and hind edge of the collare, and also the 

 cenchri, all pale luteous. Abdomen with the basal membrane whitish ; ventral 

 joints 5aml luteous, but the lateral plates black, so that the tip of the venter 

 seems at first sight black. Sheaths of the ovipositor black. Legs pale luteous: 

 tarsal tips, especially in the hind legs, obfuscated. Wings hyaline; veins black: 



