CYDNIDAE OF THE WESTERN HEMISPHERE — FROESCHNER 631 



Metapleuron (fig. 113): Evaporatorium occupying entire area; 

 peritreme transverse, elongate, trough-shaped, slightly curved, 

 reaching two-thirds to three-fourths of way to lateral margin of 

 segment; metasternum carinate, projecting between posterior coxae. 



Legs: Moderately long; in male with various secondary sexual 

 characteristics in the form of spines and angles on femora and tibiae 

 (figs. 160-164); in female without such modifications; anterior tibia 

 distinctly compressed, expanded, dorsally wdth row of seven stout 

 spines set on tubercles. 



Sternites: Strongly convex, shining, with abundant long, golden 

 hairs arising from fine punctures. 



Nymphs of this genus in the second to fifth instars (first not avail- 

 able for study) can be recognized by the row of stout pegs on the 

 margin of the head, four on the apex of the clypeus — in this respect 

 being like the adults. 



Type of genus. — Cydnus spinifrons Say (1825, p. 316), monobasic; 

 of Magoa StM, Magoa cribrata St&l (1860, p. 14), designated by Van 

 Duzee (1917, p. 23); of Pachymeroides Signoret, Pachymeroides 

 bolivari Signoret (1880, p. vii), monobasic. 



Distribution.— ^mnesiws is a New World ^° genus known to range 

 from Maine and Ontario west to Colorado, thence south through 

 Central America and the West Indies into South America as far as 

 Buenos Aires, Argentina. 



Discussion. — The synonymy of Magoa with Amnestus has long 

 been accepted and is supported by present findings, which included 

 study of the types of all the species that StM originally included in 

 Magoa. 



The synonymy of Pachymeroides with Amnestus is here proposed 

 because of the strong features which ally the two and the very weak 

 separating characters. For separation Signoret rehed most heavily 

 on the condition of the 4-segmented antennae as contrasted to the 

 5-segmented condition in typical Amnestus. While such a reduction 

 of number of antennal segments is not common in Amnestus, at least 

 some species do show it in an occasional specimen. Therefore, it 

 certainly cannot be considered a reliable generic separation. A second 

 structural difference between these two nominal genera was the 

 "absence" of evaporatoria in Pachymeroides. But even this may be 

 looked upon as a matter of interpretation as greasy specimens fre- 

 quently have shiny mesothoracic and metathoracic pleurae and 

 superficially appear to be without the "plaques mates." The generic 

 separation of bolivari from all the other species of Amnestus does not 

 appear sound when these weak separations used by Signoret are com- 



lo One specimen (in MCZ) of pusio (St&l) labeled " Madagascar" must be a case of mislabeling, or at most 

 a stray specimen carried into that part of the world by the agency of man. 



