178 



HYMENOPTEPtA. 



or it is indented, as in Mutilla. The ton^ie is shorter than usual. 

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

 hind. The meso-scutum is squarer than usual, while the meso- 

 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 bod}-, be- 

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

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

 different genera. In Myrmosa the neuration closely approaches 

 that of Sap3^ga, while in the lai'ger, 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- 

 trypidm, the veins of the wings being absent, while the 

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

 in that family.. The wingless female is XQxy different, 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. contracta Westwood is found in "Carolina." 



In the female MetJwca the eyes are verj^ long, and the seg- 

 ments of the abdo'men are widely separated, much as in the 

 ants. MetJwca Canadensis Smith is shin- 

 ing black, and slightty villose. 



The species of Myrmosa may be known 

 by the very short clypeus, the broad ver- 

 tex, and the rings of the abdomen of the 

 ^ I male being unusually contracted. The 



Fig. 107. abdomen of the female is cj^lindrical, 



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 widel}^ distributed. We 

 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 antennaj 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 entirel}' black. 



