1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 523 



are of the same type as the rest of the group. The female, however 

 has the genital plates distinct, somewhat resembling arcta. 



88. L. heterodoxa Horu. 



Not in the Museum collection; it was collected in Arizona. Dr. 

 Horn kindly gave me both sexes for study. The sexual structures here 

 show a very decidedly greater development than in the tristis group, 

 in both sexes. The claspers of the male are symmetrical, rather 

 slender, and curved, barely united in front. In the female there is a 

 peculiar development of the inferior plates, which is unique. There is 

 no trace of superior plate or pubic process. 



89. L. tusa Horn. 



Not in the Museum collection. Dr. Horn kindly allowed me to study 

 a specimen from his collection. The genitalia of the male are very dis- 

 tinctive and represent quite a peculiar type, much higher than the po- 

 sition of the species in the series, or indeed its appearance, would in- 

 dicate. The female has not been studied. 



90. L. maculicollis Lee. 



Not in the Museum collection. The species is from lower California. 

 No dissections were made of this species, as it looked too frail to risk 

 the softening necessary, and material was scarce. 



91. L. nitidula Lee. 



Not in the Museum collection. Also from lower California, and not 

 studied for the same reason given for the preceding. 



As the result of the preceding studies the number of species is in- 

 creased from 81 to 91. Two species of Dr. Horn's list are dropped — 

 ciliata, referred as a synonym of ilicis, and longicornis, which turns out 

 not North American. Of by far the greatest number of species both 

 sexes are figured — of nearly all one sex is represented. Altogether 

 there are nearly 300 figures. The task has not been a light one nor 

 has the work been hastily done. At present writing eleven mouths 

 have elapsed since the first specimens were taken for the season of 1888, 

 and much more than a year since I made the notes on the Museum col- 

 lection which I have incorporated here. The paper was not begun nor 

 intended as a contribution to systematic entomology. Dr. Horn's ar- 

 rangement is unexceptionable, and the aim of his paper — the knowl- 

 edge of the species — was fully accomplished. My own work tends 

 rather to call attention to a set of structures that must eventually be 

 studied more closely by the systematist. They render the identifica- 

 tion of a species both certain and easy, and will often solve doubts as 

 to specific identity or distinctness. The few species which I have de- 

 scribed have not been sought to gratify a desire to describe, but simply 

 to complete the work. Further collections in new localities will un- 

 doubtedly increase the number of species, and of course also our knowl- 

 edge of their habits. As it stands at present ice do not Jcnow positively 

 the larva of a single species of Lachnosterna. It ought not to be difficult 



