298 A. L. MELANDER. 



ture of the petiole of the abdomen is not a character of sufficient 

 importance upon which to base their separation. Even in the col 

 lection of the American Entomological Society the species are much 

 confused. 



28. Mutilla vesta Cresson (44). 



Another common species. Woods Hole, Mass., and Austin and 

 Fedor, Texas. April to October. 



The color of the erect hairs of the head and of the strongly spined 

 legs varies from red to black. Most of the Eastern specimens differ 

 from the typical vesta, although the typical form is found with them 

 also. The following variations seem to be fairly constant, and may 

 be tabulated : 



Vesta. — Striae of pygidium suddenly interrupted apically, the tip 

 smooth and subshining ; ventral keel of the first abdominal segment 

 twice toothed, as represented by the figure, and gradually sloping 

 off in front. Texas, Massachusetts. (Fig. 16.) 



Var. a. — Striae of pygidium more or less interrupted, the apical 

 portion opaque and granular; ventral keel of same type, but not 

 angular. Massachusetts. 



Var. b. — Striae of pygidium entire ; carina of first ventral segment 

 strong, truncate anteriorly, as in figure 17. Massachusetts. 



These three variations can be distinguished from the next variety 

 by the rounded spots of the second dorsal segment, the structure of 

 the petiole, and the finer irregular striae of the pygidium, which 

 number about fourteen and are confused with numerous shorter 

 striae. 



Var. c. — Striae of pygidium straight, entire, deep and coarse, 

 numbering not over twelve, without short striae in the interspaces; 

 ventral keel shaped as in the figure. The lighter spots of the second 

 dorsal segment are confluent. Five specimens, Woods Hole, Mass. 

 Because of its close similarity to the other forms of this exceedingly 

 variable species in form, sculpture and color, it is thought best not 

 to give this insect specific rank. (Fig. 18 ; petiole.) 



29. * Mutilla canella Blake (46 and 75). 



Mutilla canella Blake % . 

 Mutilla rugulosa Fox £> . 



We have one female specimen from Woods Hole, Mass., August, 

 which appears to belong here. The male is not rare at Fedor, Texas. 

 May- June. 



