32 MISCELLANEOUS STUDIES 



Tribe Chaitophorini Wilson (Lachnidea Mordw. and 

 Chaitopheri Mordw.) 



Wilson, Can. Ent., vol. 42, pp. 385-387, 1910. 



This tribe as considered by Wilson contains the following genera : 

 Arctaphis, Chaitophorus, Symydobius, Thoniasia, and Sipha. The 

 author has followed Wilson's classification, having added, however, 

 two genera described later by Essig: viz., Micrella and Fullawaya. 

 Essig's genus Eichochaitophorus is a synonym of Arctaphis Walker 

 (see discussion under no. 27). Mordwilko's groups Lachnoidea and 

 Chaitophori are both included in this one tribe. In the former, Mord- 

 wilko includes Symydobius and Pterochlorus, and in the latter, 

 Cladobius, Melanoxanthus, and Chaitophorus. Both Cladobius and 

 Melanoxanthus are included in this paper in the tribe Pterocommini, 

 being synonyms of the genus Pterocomnia Buckton. Following is a 

 description of the tribe Chaitophorini as given by Wilson (op. cit.) : 



Antennae, except in Sipha, always six-segmented; in Sipha there are but five. 

 Length variable; antennal tubercles wanting; antennae, legs, and body covered 

 with hair-like bristles. Fore wings with two oblique veins and cubitus always 

 twice forked; hind pair with two cross veins. Nectaries (cornicles) variable in 

 length and size, but never longer than one-tenth the length of the body. The 

 genera in this tribe are somewhat similar to those in the tribe Callipterini, but 

 are easily distinguished by the shorter and heavier antennae and legs, as well as 

 by the finer and more hair-like bristles. 



The following key to the Californian genera has been adapted from 

 Wilson and Essig : 



1. Spur of sixth antennal segment at least three times as long as the segment 2 



Spur not three times as long as the segment. Cauda broadly rounded and 



without knobbed tip 4 



2. Spur more than five times as long as the segment; cornicles longer than the 



base of the sixth segment Chaitophorus Koch 



Spur of sixth segment not more than five times as long as the segment; corn- 



icles not longer than the base of the sixth segment 3 



3. Cauda a knob on a quadrangular base (fig. 69). Spur about five times as 



long as sixth segment Arctaphis Walker 



Cauda tapering to a blunt tip which is usually straight across, not being 



rounded or constricted at the base (fig. 70). Spur but slightly more than 

 three times as long as the sixth segment _ Micrella Essig 



4. Spur of sixth segment shorter or scarcely longer than the segment; antennae 



nearly as long as the body Symydobius Mordwilko 



Spur considerably longer than sixth segment; antennae about one-half the 



length of the body _ 5 



5. Cornicles absent ; body with lateral tubercles Fullawaya Essig 



Cornicles present ; lateral body tubercles wanting Thomasia Wilson 



