180 



NOTES ON LACHNOSTERNA FUSCA, Auct. 



By John B. Smith. j 



Among the injurious insects most commonly referred to in economic 

 papers and reports the above species stands in the first rank. It is 

 known universally as the parent of the " white-grub," and a very gen- 

 eral impression prevails that there is but one grub of that kind. As a 

 matter of fact, there are quite a number of species which are almost 

 equally as common, locally or seasonally, as the L. fusca^ and the injury 

 done by them has, according to the usual rule, been saddled on the uni- 

 versal scai^egoat, which in this genus has been fusca. Until very lately 

 entomologists have been entirely at sea astotbe specific limitations of 

 our species. It was an understood matter that they were very variable 

 and afforded no safe characters for differentiation. In jS"ovember, 1887, 

 in Trans. Amer. Entom. Soc, XIY, 209-296, was begun a i:)aper by Dr 

 G. H. Horn, issued early in the present year, which at last brought 

 order out of confusion, and enabled us to arrange our material with 

 some degree of satisfaction. 



Among the species recognized, /i^sca is the one credited by Dr. Horn 

 with the greatest amount of variation, and several races are indicated, 

 which are yet said to present no distinctive characters. At the same 

 time Dr. Horn does not seem to be quite sure that there is after all but 

 one species, even though the characters separating them are not ob- 

 vious. The collections of the National Museum are very rich in speci- 

 mens and species in this genus, and large collections made this spring, 

 and obtained from various parts of the country, have enabled me to 

 somewhat supplement Dr. Horn's work on the genus. Attention once 

 drawn to a very strongly marked character of the genital structure of 

 both sexes, investigation was continued along this line with the most 

 gratifying results, since the characters afforded are constant, strongly 

 marked, and readily verified. At the present time, only the diversities 

 observed in the species known as fusca will be described, further notes 

 made on the large majority of our other si)ecies being reserved for 

 publication when more complete. ' d 



Studied in the light of the genital structure, /«sca resolves itself into 

 four distinct si)ecies, each almost equally common at special localities, 

 but not at the same. 



The characters in which all these forms agree are as follows: Body 

 not ])ubescent above, shining; antenna? lO-jointed, the club of male 

 always longer than that of the female; clypeus not densely punctured, 

 the margin moderately retlexed, feebly einarginate; lateral margin of 

 thorax not serrate, nor distinctly angulate; the posterior tibire are trun- 

 cate at apex, without a trace of sinuation at the base of the fixed si)ur 

 of the male; this spur is of moderate size; claws strongly toothed at 



