40 ENTOMOLOGICAL SOCIETY 



the latter species, consisting of a row of long hairs in the 

 male on the first antennal joint. He called attention also to 

 Dr. Horn's recent revision of the North American species 

 of Ochthebius, and spoke of the remarkable geographical 

 distribution of these aquatic insects. Species of this genus 

 occur in Florida, western Pennsylvania, Vermont, Michigan, 

 and throughout the western part of the country, but not a 

 single specimen had hitherto been found east of the Alle- 

 ghanies from Maine southward to Georgia. 



Mr. Marlatt presented the following communication : 



THE XANTHIUM TRYPETA. 



Trypeta cequalis L/w. 

 BY C. L. MARI, ATT. 



Trypeta cequalis L/oew : Monog. Dipt. N. A., I, p. 86 ; Tab. II, f. 20, 



1862 (description of male). 

 Trypela cequalis Loew : Monog., etc., Ill, p. 308; Tab. X, f. 20, 1873 



(description of male and female ; referred to sub-genus Euaresta]. 

 Trypeta (Euaresta] cequalis Lw. Osten Sacken : Cat. Dipt. N. A., 1878, 



p. 194. 

 Trypeta (Euaresta) aqualis Lw. Osten Sacken : Bull. U. S. Geol. Surv. 



Ten, Vol. Ill, No. i, p. 345 (species mentioned as very like T. 



cequalis L/w.). 



The species of Xanthium are such notorious weeds, and are 

 so widespread and troublesome, that a knowledge of any im 

 portant insect enemy becomes of interest. The enemies of 

 noxious weeds, whether insects or fungi, are, I am aware, of 

 second-rate economic importance, as it is only in connection 

 with careless and negligent culture that such plants are 

 allowed to multiply, and thus furnish opportunity for the in 

 crease of their insect and other enemies. That such plants 

 are and always will be allowed to flourish, renders any natural 

 check important. This consideration, together with the scien 

 tific interest attaching to a knowledge of the habits of the in 

 sect, leads me to put the following facts on record. 



Some years ago my attention was drawn to the fact that the 

 larvae of a dipteron, bred in the seeds of a cockle-bur, or 

 Xanthium, by Mr. W. T. Swingle, of the Kansas State Agri 

 cultural College at Manhattan, Kansas, who came across the 

 larvae while making some studies, I believe, of the germination 



