THE CANADIAN ENTOMOLOGIST. 147 



The lateral plates are mostly thin and partially transparent, the result often 

 being an appearance confusing to one not understanding their structure, 

 especially so when the epigynum is examined in a liquid medium. Various 

 published drawings of epigyna represent the septum as narrowest at the 

 free surface and gradually broader and broader toward the base or dorsal 

 part in cases where the free edge in reality is widely extended horizontally 

 over the basal portion. 



The function of the median body, or variously termed " process," 

 "ovipositor," " finger," etc., seems clearly to be that of a guide to the male 

 embrolus, controlling the course of the latter and facilitating its entrance 

 to the spermatheca. Intimately associated with specific and generic 

 differences in the epigynum are naturally corresponding differences in the 

 male palpus. The unusual structure of epigynum in Lycosa fu/chra. 

 Keys ( = Z. Kochii, Keys, of Em., Banks, etc., but nee. Keys; = Z. 

 Purcelli, Montg., the true Kochii being a western species), is matched by 

 an equally, if not more, peculiar palpus in the male. The characteristic 

 epigyna of Z. ocreata, gracilis { = verisimilis, Montg.), bilineata and their 

 allies (group Sc/iizogy?ia), are likewise associated with correspondingly 

 peculiar palpal organs. 



The epigyna in the genus Pardosa, agree in having the depressed 

 area relatively large and deep on each side adjacent to the opening of the 

 receptaculum, the depression anteriorly becoming narrower and shallower, 

 usually strongly so. The depression in front, in fact, is often but slightly 

 indicated, although ordinarily more developed at its extreme anterior end 

 than in the region immediately posterior to that part. The guide frequently 

 quite fades out in front of the middle, leaving the depression 

 anteriorly undivided {P. lapidicina), and in other cases it is relatively but 

 weakly indicated in that region. Sometimes the depth and width of the 

 furrows increase very gradually from in front posteriorly, as they do in 

 P. 7iealota (an undescribed Texan species allied \.o littoral is) ^ but leaving 

 the guide narrower anteriorly. In other forms the deeper posterior areas 

 or fovese may be formed abruptly, as is very conspicuously the case, for 

 example, in P. sternalis and P. atra. The posterior foveae may be 

 relatively very large, with the shallower front region much reduced 

 {Groenlandica, bruimea) or relatively small {sternalis, atra). In 

 xerampelina, Keys {^tachypoda, Th., and Montana, Em., etc.) the 

 transverse arms of the guide are but weakly developed, and the median 

 septal part widens conspicuously anteriorly. 



In Lycosa, conditions as to the median depression are nearly the 

 reverse of those found in Pardosa, the furrows being deepest and widest at 



