H. C. FALL 479 



uniformly diffused without trace of serial arrangement at any 

 part; lustre dull; eyes small, very remote, front without ocular 

 lines; front thighs not stouter, all the tibiae without apical spurs, 

 front claws of male not enlarged. Ave. length 3.1 mm. Arizona. 



Head evenly very densely punctate, one or two minute obscure rufous flecks. 

 Eyes very small, separated by rather more than twice their vertical length in 

 the male. Antennae short, subclavate, black, brownish rufous toward the 

 base, barely or scarcely half the length of the body (cf), tenth joint less than 

 twice as long as wide. 



Prolhorux moderately transverse, somewhat narrowed in front, sides l)roadly 

 arcuate. 



Elytra uniformly very denselj' punctate throughout, the narrow interspaces 

 between the punctures fineh^ wrinkled. 



Femora black, tibiae and tarsi brownish. 



Length 2.9 to 3.35 mm.; width 1.45 to 1.85 mm. 



Distribution. — Arizona: Santa Rita Mountains, May 30 (Hubbard & 

 Schwarz), type male in Nat. Mus. Coll.; WiUiams (Wickham). 



Two males only of this remarkable species have been seen. It 

 is most nearly related to hepaticus, with which it agrees in its 

 small very distant e^ves and crural structure, and which is not 

 unlike it in its short feebly incrassate antennae. 



Biological Notes 



Very little is known, or at least published, concerning the 

 food plants, habits, etc., of our species of Pachybrachys. An ap- 

 peal to Air. Schwarz for any data known to him or possessed by 

 the Bureau of Entomology at Washington, brought the following 

 reply. "The species of Pachybrachys are so troublesome because 

 most of our eastern species, and apparently also many of our 

 western ones, do not appear to have any definite food plant in the 

 imago state, and because their larvae (which unquestionably are 

 all sac-bearers) are so difficult to find, and do not feed upon the 

 foliage of plants. In fact Mr. Barber and myself have bred only 

 a single species, P. tridens, from larvae found crawling under old 

 leaves on the ground. The imago of P. tridens is also the only 

 eastern species which seems to have a definite food plant, viz. — 

 Rhus toxicodendron. Some of the larger species found by Barber 

 and Schwarz at Williams, Ariz., occurred exclusively on Pinus 

 engebnanni, and some of the smaller species from the desert region 

 of Arizona have also definite food plants, but I failed to obtain 

 the names of these plants from the poor specimens I gathered. 



TR.\NS. AM. ENT. SOC, XLI. 



