26 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



Dr. L,eConte in 1859 first recognized the genus in America 

 and referred to it a new species, L. complex, which, being 

 the species first described in the genus, should stand as its 



type- 

 In 1866 Pascoe erected the genus Illestus, and referred to it 



a new species from Mexico, /. terrains Pasc. He separates 

 this genus from Lasconotns mainly by the character of not 

 having the side margins of the head covering the eyes. As 

 pointed out by Dr. Horn (1878), this character is well marked 

 in but a few species, becoming gradually less until it is scarcely 

 traceable, and he concludes that Illestus is synonymous with 

 Lasconotns. I have seen three specimens of /. terrenus Pasc. 

 collected at Toluca, Mexico, and determined by Dr. Sharp. 

 They are quite different from any Lasconotns known to me in 

 the following readily observable characters. The anterior coxal 

 cavities are apparently open, but in fact very narrowly closed 

 behind, the tibiae scarcely everted externally and armed with 

 a row of close-set spines instead of two prominent spines and 

 several small ones, and the terminal segment of the maxillary 

 palpi truncate, not at all rounded at the apex. In Pascoe's 

 figure the antennas are shown as twelve-segmented. This is 

 obviously an error in drawing; it is not observable in the 

 specimens. 



The genus Lasconotns is quite readily divisible into well- 

 marked groups, but there seems to be no sufficiently well- 

 defined, constant structural character for separating them as 

 distinct genera. The fore tibiae are usually everted externally, 

 though in some species merely rounded, and always armed at 

 the apex with two prominent spines. Several smaller spines 

 extend from the outer to the inner apical angle, which is 

 armed with two short, straight spurs. The anterior coxal 

 cavities are closed behind the posterual epimera, broad behind 

 the coxae. There is considerable range in size and general 

 outline, though within the species these characters are very 

 constant. The head, antennae, ventral surface, and especially 

 the elytral and pronotal sculpture, furnish excellent and re- 

 markably constant taxonomic characters. 



Very little is known concerning the exact habits of the 

 species. They are usually found associated with various 

 scolytids inhabiting coniferous trees. Principal among these 

 are Pityophthorns (Tomicns}, and at least two species are 

 found with Phlccosinus. Whether they are commensals or 

 predaceous is not well known. The mouthparts, so far as I 

 have examined, would indicate a predaceous habit, but even 

 if so, whether they prey upon the scolytids themselves or the 



