CYDNIDAE OF THE WESTERN HEMISPHERE — FROESCHNER 377 



Subfamily Cydninae 



Cydnides Billberg, 1820, p. 70. 



Diagnosis. — Technically, members of this subfamily may be rec- 

 ognized by the arrangement of the trichobothria (see discussion of 

 subfamilies on page 352) or the venation of the metathoracic wing shape 

 of radial cell plus absence of hamus (see page 353). More readily 

 available means of determination, however, have been pointed out 

 in the key to subfamilies. The following features must be used 

 together: lack of claval commissure, front tarsus arising at or near 

 apex of tibia, and the presence of a lateral, submarginal row of seti- 

 gerous punctures on the pronotum. 



Description. — Head: Margin entu-e, not crenulate; antennae 4- 

 or 5-segmented. 



Scutellum: Long, surpassing apices of clavi, latter not forming 

 commissure posterior to scutellar apex. 



Thoracic pleurae: Posterior margins all well developed, propleuron 

 with strong convexity posterior to depression; mesopleuron with pos- 

 terior margin touching or overlapping metapleuron for most or all 

 of its width; metapleuron with posterior margin reaching to base of 

 abdomen for its full width and completely covering internal part of 

 hind coxa. 



Legs: Weakly or strongly modified. Anterior tibia of all strongly 

 compressed, a row of stout spines dorsally; middle legs feebly or not 

 modified; posterior legs variously terete or compressed, straight, 

 curved, or sinuate, rows of spines regularly spaced or crowded on dorsal 

 and ventral margins; tarsi present on all legs, segment II shortest, 

 subequal m diameter to I and III. 



Sternites: Sutures nearly straight, not strongly sinuate laterally; 

 trichobothria arranged differently on each segment^ — on VII arranged 

 in transverse row behind spiracle, on VI to III successively the ventral 

 trichobothrium shifts farther forward until on III it lies mesad or meso- 

 anteriorly to the spiracle (fig. 172). 



Terminalia: Male genital capsule opening dorsally; female plates 

 well developed, mostly exposed (fig. 186). 



Type of subfamily.— Genus Cydnus Fabricius (1803, p. 184). 



Distribution. — Available information showed that the full geo- 

 graphic range of the family — worldwide, in all zoogeographic regions — 

 is occupied by members of this subfamily. 



Discussion. — This subfamily not only contains more genera and 

 species than all the other subfamilies combined but appears also to 

 show greater contrasting extremes of morphological modifications. 

 On the basis of the wmg venation, trichobothrial arrangement, and 

 the head structure, the Cydninae appear to be more closely related 



