24 



PROC. ENT. SOC. WASH., VOL. 24, NO. 1, JAN., 1922 



Leconte and trapezoideus Leconte) has the lateral margin 

 straight or simply curved, but in all cases entire. Within 

 these two groups there are many variations of shape which have 

 proved to be of specific value. On the other hand 

 unquestionably distinct species tend to group 

 about certain genitalic types. The presence or 

 absence of an angle on the outer margin of the 

 lateral lobe is not consistently correlated with 

 any recognized external character. 



External genitalia of female (fig. 26, M. communis 

 Gyll. & fig. 27, M. sp.). Throughout the genus 

 the ovipositor is a slender, rather depressed, trans- 

 parent, cylindrical tube, ending in a bulbous 

 structure which bears the genital valves (GV) and 

 the terminal styli (Sty). The valves and styli 

 are finely and sparsely haired. The genital valves 

 are elongate and spatulate, articulating laterally. 

 Each is surmounted near its apex by a cylindrical 

 stylus about one-third as long as the valve. Show- 

 wing conspicuously within the cylindrical part of 

 tne v ipsitor, and connecting posteriorly with 

 hyshpiVanZwa\u- a. less conspicuous pair in the bulb, is a pair of 

 narrow, elongate, flexible chitinous rods (Rd) 

 which serve to strengthen the ovipositor when it is thrust into 

 the nidus at oviposition. As the ovipositor belongs more 

 properly to a consideration of internal, rather than external 

 anatomy, a more detailed description is left for future discussion. 

 Although the writer has not studied the female genitalia as 

 carefully as those of the male, it is apparent that they do not 

 offer such satisfactory characters as the male aedeagus does. 



EXPLANATION OF ABBREVIATIONS USED IN THE FIGURES. 



A 1, A2 first and second anal vein. 



AJ antennal joint. 



An anus. 



Ant Fov antennal fovea. 



'ANP anterior notal wing process. 



Ax axillary sclerites by which the wing articulates with the scutum 



of the metathorax. 



AxC axillary cord (2, of mesothorax; 3, of metathorax). 



B basalar plate; the parapterum of Snodgrass. 



Bs basal piece of aedeagus. 



Btp basistipes, a subdivision of the true stipes; the "stipes" of cole- 



opterists. 



Cd cardo. 



description of this species and reference to this figure see Proc. Ent. 

 Soc. Wash., vol. 23, no. 9, 1921, p. 211. 



