MELANOTUS — QUATE AND THOMPSON 



not include the projection of posterolateral "hind angles." The width 

 is measured as the widest part of the pronotum before the hind angles 

 and is not affected by their expansion if they are wider than the rest 

 of the prothorax. The relation of the antennal length to the pronotum 

 used in the descriptions refers to the distance before or beyond the tip 

 of the hind angles, which the antenna reaches when stretched along 

 and parallel to the side of the pronotum. 



As an indication of size, we have measured only the length of the 

 elytra. This is more accurately measured than the whole length of 

 the insect and is as useful as an indication of its overall dimension. 



The genitalia of both sexes are important taxonomically, but the 

 parts are simple and easily defined. Following the terminology of 

 Snodgrass (1957), the male genitalia consist of a central "aedeagus" 

 (median lobe) which is flanked by a pan- of "parameres" (lateral lobes, 



Figure 3. — Distribution of species. 

 O Melanotus longulus longulus 

 ® M. I. oregonensis 



gonostyli). These are supported by the "phallobase." The para- 

 mere may be plain at the tip or expanded into an "apical blade." The 

 taxonomically important parts of the female genitalia (fig. 5) are the 

 large membranous sac, the "biu-sa," which contains spines of various 

 shapes and number, and the "accessory gland" and "spermathecal 

 duct," which arise from the bursa. A more detailed morphological 

 description was given by Becker (1956); he also described the tech- 

 niques used in dissecting the female genitalia. It is only necessary to 

 add that light reflected from the substage muTor of a stereoptic micro- 

 scope is helpful in seeing the delicate spermathecal duct, its divertic- 

 ulum, and accessory gland. 



Bibliographic references are intended to be complete ; catalog refer- 

 ences (Leng, 1920; Schenkling, 1927) ai-e given only when new infor- 

 mation is involved. 



