368 



THE AlCERICAN 



the club DOt quite as long as the two preceding joints put to- 

 gether, and when viewed in one direction much wider than 

 they are. Thorax as in Figure 8 G. Collar very short, trans- 

 verse; parapsidal grooves obsolete behind. Abdomen when 

 viewed from above, (^ oval or sometimes almost obovate, 9 

 ovate; when viewed in profile, cT elongate-oval or almost 

 linear, 9 triangular with the apex of the triangle downwards . 



[Fig. 7.] 



Semiotellus chalcidephagus, n. sp. $ (Fig. 7, a) — Blue- 

 black or dark indigo-blue. Head finely and confluently punc- 

 tured and scarcely polished. Antemiie pale rufous, darker 

 towards the base, the flagellum not pubescent, and the fla- 

 gellar joints indistinctly separated. TAoraa; sculptured as 

 the head. Abdomen almost sessile, depressed, flattened 

 above, rounded below, polished, with a few short whitish 

 hairs towards the tip; color less blue than the head and thor- 

 ax, and with coppery reflections especially below, Legs 

 black, with the tibiae and tarsi, except the tips of the latter, 

 pale rufous, the tibiae occasionally being basally clouded 

 with black on the outside. Wings hyaline; front wing with 

 a dark smoky cloud extending backwards irom the subcostal 

 vein, from where that vein first touches the costa to the tip 

 of the ramus or branch, but not quite attaining the hind edge 

 of the wing; veins brown, much paler towards the base of 

 the wing. Length, 9 0.09— 0.11 inch. 



The (f (Fig. 7, 6) differs as foUows from the $ : 1st, the 

 antemije are longer, with the flagellar joints pubescent and 

 distinctly separated, joints 1 and 2 rufous, 8 — 9 dark brown; 

 2nd, the abdomen is subiietiolate, narrower, its tip acute, 

 and with the penis often protruded, the coppery tinge stronger 

 than in 9 ; 3rd, the front wing has no dark smoky cloud. 

 Length, (f 0.08— 0.10 inch. 



Described Irom 18 <? 15 $ ; namely, 17 cf bred from last 

 year's barley galls June 11th — 22nd, 1 <? sent to me by Mr. 

 Pettit from Grimsby, C. W. , 14 $ bred from last year's bar- 

 ley galls June 14th— 28th, and 1 9 cut out Sept. 10th from 

 barley galls of the same year's growth. 



In but very few other insects, as in this species, does one 

 sex have a distinct dark cloud on the wing and the other sex 

 none at all. But in a European May-fly, Potamanihus mar- 

 ginatuSy Zetterst., as I was informed long ago by Dr. Hagen, 

 the cT has a dark patch on the front wing and the female has 

 perfectly hyaline wings. In Myodites Walshii, Lee— a beetle 

 described from specimens furnished by myself— the converse 

 rule holds good, for here the cT has perfectly hyaline wings 

 and the 9 has a large dark patch on her wings, as in the 

 Chalcidian now treated of. 



Larva of the above. — Length 0.13 inch, from 4:^ to5 times 

 as long as wide, the body a little tapered towards the anus. 

 Color a pale glaucous green, the head of a somewhat darker 

 shade, as also joints 3--10 of the body. Jaws dark-colored, 

 transversely arranged in repose, by which last character 

 this larva may be distinguished at once irom the Joint- worm 

 upon which it preys, for the latter always has its jaws direct- 

 ed backwards m repose at an angle of about 45° with the axis 

 of its body, instead of being directed sideways at an angle 

 of 90'^ with the axis of its body . It differs also from the Joint- 

 worm in the less reliable character of being greenish- white, 

 instead of bright yellow. 



Two distinct species of Chalcis flies were found by Ilan-is 

 and Fitch to be parasitic in Joint- worm wheat-galls received 

 from Yirginia, and very beiefly described by these authors : 

 1st, a Torymus, Q with an ovipositor nearly as long as her 

 body, and 2nd, a Pteromalus (Harris' Inj. Ins,, pp. 556-7). 

 This last differs from my species in having the antennas black 

 with the scape bright copper-color, in the femora being pale 

 yellow, and in the tibiaj being blackish, besides other less 

 obvious distinctions. 



SUBFAMILY ENCYETIDES, Westw. 



Antigaster, new genus —The new genus to which the fol- 

 lowing new species belongs is one of the most anomalous 

 known to science. Many other genera are more or less con- 

 tractile, e. g., Agathidium, Clambus, Leiodes and Sphcero- 

 mor^hus in Coleoptera, and the genera Eurytoma and Deca- 

 toma and the different genera of Ckrysididce, in Hymenoptera. 

 But all these, when they roll up in a more or less complete 

 ball to protect themselves from their foes, roll up downwards 

 with a convex back, whereas Antigaster rolls up upwards 

 with a convex belly and sternum. In the only group of in- 

 sects known to me that approximate to Antigaster in this 

 peculiarity— SiopA^/Ziwidee in Coleopterar— the anus is cm-ved 

 up over their backs to adjust their wings under their very 

 short elytra, and never, so far as I have been able to see, for 

 protection against their enemies by the assumption of a con- 

 tractile attitude. It is very true that certain species of these 

 beetles, when approached in a threatening manner, curve 

 the anus over their backs ; hut this appears to me to be simply 

 analagous to a similar proceeding on the part of LibelluHdeSt 

 wliich when roughly handled generally curve the anus under 

 the thorax, after the fashion followed by the (^ LibelluUda 

 in copulation. In both these cases an attitude which is nor- 

 mally and habitually employed for entirely different purposes, 

 is abnormally and occasionally adopted by way of a threat. 



Antigaster, n. gen. — $ (Fig. 9) Body capable of rolling up 

 the contraiy way to a Chrysif. Antennae as in Figure 9, d, 10- 

 jointed (Sc.-f-84-Cl.), springing from near the lower internal 

 corner of the eye, each antenna about t\\'^ice as distant from 

 the other one at its origin as it is from the eye; basal part of 

 the scape much curved inwards; the flagellmn gradually 

 clavate from base to near the tip. No antennal groove. 

 Prothorax but slightly attached to the thorax, very large, 

 distinct, and prolonged upwards in a lateral more or less 

 acute and curved hook, the tip of which is directed forwards. 

 Mesothoracic scutum (Fig. 8, A, b) foiTning along with the 

 hind angle of the prsescutum (a) a square excavation adapted 

 to receive the head in repose; scutum and prsescutum closely 

 united together, but connected only by loose membrane 

 laterally with the pleura and behind with the scutellum (c) 

 and postscutellum (d) , so as to be capable of being elevated 

 behind. The scuteUum and postscutellum similarly capable 

 of being elevated in front, in which case the mesonotum, 

 when viewed in profile, lies in an angle of 80°: this is the 

 position of repose. The same parts, when depressed for 

 flight or walking, and viewed in profile, lie in a gentle curve 

 forming a circular arc of only 30°, instead of an acute angle. 

 Collare very short, and only visible when the mesonotal sub- 

 segments are depressed, its hind edge uniting with the tri- 

 angular praescutum in a quadrant, the convexity of which is 

 towards the head. Abdomen clavate, its upper surface flat 

 or a little excavated, its lower surface rounded. Tarsi all 

 5-jointed, with the basal joint the longest. Front femora 

 and tibiEe robust. Middle legs with their coxa3 springing 

 from the extreme hind end of the mesostenium, the two coxai 

 close together, the femur much depressed and with its inner 

 edges perfectly straight, so that the two femora imite in aa 

 close and smooth a joint as do the elytra of most beetles , thus 

 forming a broad plate to protect the lower surface of the ab- 

 domen in repose; tibial spur very long; first tarsal joint 

 widely compressed and finely dentate below, and tarsal joints 

 2 — 5 unusually robust. Hind legs with their coxeb springing 

 from the tip of the metathorax, but wide apart so as to admit 

 the middle legs to pass between them in repose. When all 

 the four hind coxaa are airected backwards, the tip of the 

 middle coxaj reaches as far aa the middle of the hind coxs. 

 Front wings with the subcostal vein uniting with the costa 

 about half way to the tip of the wing; ramus or stigmal 

 branch springing Irom the costa at an angle of 45^^, straight, 

 clavate, and fully one-sixth as long as the extreme breadth 

 of the wing. Subcostal vein in the hind wing somewhat in- 

 distinct. The (f is unknown. 



In the only other Encyrtides in my collection, namely 1 



