158 THIRD ANNUAL REPORT OF 



would gnaw their way through the shell of each egg. This little fly- 

 belongs to the great Chalcis family, and though scarcely more than 

 0.02 inch long, it can jump to the distance of several inches. Its 

 wings, especially the hind ones, are beautifully fringed with hairs. It 

 is inconspicuously marked, the body being dark brown with the an- 

 tennas and legs pale, and the wings iridescent. The highly magnified 

 outlines at Figure 72 will convey a good idea of its appearance, a 

 showing the fly with wings folded on the back, b one of the front 

 wings, c one of the hind wings, d one of the legs, and e one of the 

 antennas. 



I shall leave the proper determination of this insect to those who pay more particular attention 

 to the Chalcidjdje. It comes nearest the genus Trichogramma, Westw., and may be provisionally 

 called Trichogramma (?) minuta. It differs from that genus and from all other Chalcididan 

 genera with which 1 am acquainted, in the antenna 1 being but 5-jointed (scape, plus 4 joints), the 

 scape stout and as long, or longer, than joints 2, 3 and 4 together ; joints 3 and 4 small and to- 

 gether as long as joint 2 ; 5 very stout, fusiform and as long as 2, 3 and 4 together. The legs have 

 the trochanters stout and long, the tibia not quite so long nor so stout as the femora, and with a 

 long tooth ; the tarsi are 3-jointed, with the joints of equal length and with the claws and pulvilli sub- 

 obsolete. The abdomen is apparently 6-jointed, the basal joint wide, the 2nd narrower, 2—5 in- 

 creasing in width till 5 is as wide as 1. The ovipositor of $ extends a little beyond the apex, and 

 starts from the anterior edge of the 5th joint. 



The Disippus Microgaster. — The third parasite which also very 

 [Fig. 73.] commonly infests the last brood of larvas, and kills its 

 victim during the second period, is a little black four- 

 winged fly belonging to the genus Microgaster. The para- 

 sitic maggot eats its way out just before the Disippus larva 

 gets ready to build its winter tenement, and spins a pale 

 yellowish cocoon of silk, either upon the back of its victim 

 or upon the leaf close by ; and from this cocoon the fly soon after- 

 wards issues. Figure 73, which represents the Army-worm Micro- 

 gaster enlarged, will convey a good idea of its Disippus relative. 



The genus Microgaster is a very extensive one, and the species 

 have not yet been well studied in this country. They are all of small 

 size, and in many instances resemble each other so closely that they 

 can only be satisfactorily studied in connection with their habits and 

 the particular larvae which they infest. Some appear to confine their 

 attacks to one particular kind of caterpillar, while others infest alike 

 many different species. Thus the one under consideration not only 

 infests the Disippus larva, but I have also bred it from that of the 

 Golden-rod Gall-moth (Gelechia gallcesolidaginis, Riley) obtained 

 from Canada ; which indicates it to be a widely distributed species. 



Microgaster limenitidos, N. Sp. — <? $• Length 0.09 inch. Color pitchy-black. Antenna 

 black, about as long as body ; palpi whitish. Thorax minutely punctured. Abdomen with the two 

 or three basal joints emarginate and rugose, the terminal joints smooth and polished. Legs dusky ; 

 front and middle femora yellowish, hind femora black ; front and middle tibia yellowish, hind 

 tibia with terminal half dusky, but the spur pale ; front and middle tarsi yellowish tipped vv h 

 dusky, hind tarsi dusky above, paler below. Wings hyaline, iridescent, the nervures and sti a 

 black or dark-brown, the radial nervule, the cubital nervules and the exterior nervule of the . g 

 coidal cell, sub-obsolete. 



