1«85.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 417 

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Vol. VIII, I¥o.2r. l¥asliiiifirton, D. C. HSepti^tT, 1885. 



a darker ipetallic tinge, especially at joints, causing the flagelluni in some instances, 

 particularly in the smaller individuals, to appear dark ; jiilo whitish ; all legs honey- 

 yellow ; cosie very slightly metallic at base ; tarsi, and sometimes distal end of tibiae, 

 whitish ; abdomen black ; penis (often extruded to a considerable length) brown. 



Female {winged and wingless). — Length varies from LS™"" to 2.8"^'"' ; average wing 

 expanse, 3.75""™. Differs from male in the following respects : The antenna? are more 

 clavate, the sixth fnnicle joint slightly broader than long ; the flagellum is always 

 "black, with a slight metallic tinge, and the pedicel is usually tipped with black at 

 its distal end ; the pile is much shorter and filter than in the male. The femora and 

 the tibiae are in general of a darker brown, in which case the knees and the distal 

 third of the tibiae are whitish. The metallic luster of the thorax is more subdued, 

 and the abdomen has the characteristic female notch when seen from the side. The 

 wings are perfectly hyaline, and the veins are only faintly tinged with yellowish ; 

 the spurious veins are very faintly perceptible. 



Described from many <? and 9 specimens, only 3 of the latter being winged. All 

 bred from final larva of the Hessian Fly, collected at Cadet, Mo., by J. G. Barlow, 

 and issuing through the coarctate larva shell. 



Distinguished from other described species by the contrasting antennae in the sexes 

 and by the ovate abdomen which, when fresh, has no flattened dorsal surface. 



There, can be no question but that the wingless and winged individ- 

 uals are specitically identical. The proportion of the wingless to the 

 winged varies at different seasons and in different parts of the country. 

 Thus from a lot of puparia of the Hessian Fly, received in the summer 

 of 1883 from Missouri, there issued 31 wingless males, 28 wingless fe- 

 males, and 3 winged females. Of these, about one-third issued from 

 the straw in August, 1883, and the rest, including all the winged indi- 

 viduals, hibernated in the straw and issued in April and May, 1884. 



While, as the descriptions show, there are many very important 

 points of difference between these two species — points that would even 

 separate them subgenerically and, according to some authors, gener- 

 ically, the distinguishing features that will be most readily observed 

 by casual examination are as follows : 



Destructor is on an average of smaller size; more uniformly metallic 

 in color; has a flatter abdomen, with yellowish spot at base; has the 

 antennae similar in both sexes (generally darkest in the male), and either 

 pale-brown or blackish-brown ; has the cox£e metallic- black, the femora 

 brown or black, except toward tip ; the paler parts of legs whiter than 

 in s7ibapterus. It does not, so far as we now know, occur in the apterous, 

 condition. 



iSubapterus is on the average larger ; of darker color and less metallic, 

 with the flagellum of the antennae pale in the male and black in the 

 female ; the abdomen much more rounded and without pale spot ; the 

 coxae, trochanters, femora, and basal part of tibiae honey- yellow. It 

 occurs mostly in wingless condition. 



The jaws are brown in both sexes, but more conspicuously so in 8ub- 

 apterus, 



Proc. Xat. Mus. 85 27 



