178 HYMENOPTERA. 



or it is indented, as in Mutilla, Tlie tongue is shorter than usual. 

 The sides of tiie thorax contract in width, both before and be- 

 hind. The ineso-scutura is sqnarer tlian usual, while the nieso- 

 scutellum is much narrower and longer, and the propodeum is 

 squarely truncated behind, thus presenting a full convex surface. 

 The abdomen is not much longer than the rest of the body, be- 

 ing shorter than usual. In all these characters this family shows 

 its afTuiities to the Ants. The wings are very dissimilar in the 

 difi'erent genera. In Myrmosa the neuration closely approaches 

 that of Sapyga, while in the larger, more acute primaries of 

 Mutilla, and especially in the short outer costal cell, and short 

 open pterostigma, the latter genus differs from the others. 



The male of Scleroderma closely mimics the Procto- 

 trypidai, the vehis of the wings being absent, Avhile the 

 form of the head and abdomen also reminds us of some genera 

 in that family. The wingless female is very diiierent, having 

 more of the form of Mutilla, with a large oblong head and long 

 acutely conical abdomen. The species are minute and rarely 

 met with. S. contn'acta Westwood is found in "•Carolina." 



In the female Mcthoca the e^-es are ver}' long, and the seg- 

 ments of the abdomen are Avidely separated, nuich as in the 

 ants. 3Iethoca Canademns Smith is shin- 

 ing black, and slightly villose. 



The species of Mi/nnosa may be known 

 by the very short clypeus, the broad ver- 

 tex, and the rings of the abdomen of the 

 male being uiuisually contracted. The 

 ri?. 107. abdomen of the female is cylindrical, 



about twice as long as broad, and thickest on the second ring. 

 The rings are densely hirsute on the hinder 

 edge. Myrmosa unicolor Say (Figs. 107, 

 male ; 108, female) is widely distributed. We i 

 have taken this species in Maine, while sex- | 

 ually united, early in June. The wingless 

 female is like an ant, and is pale reddish on 

 the thorax and basal ring of the abdomen, 

 and the antennae and feet are concolorous, while the head and 

 remaining abdominal rings are much darker. It is .20 inch 

 long. The male is .28 inch long and entirely black. 



