192 SUB-FAMILY EUCOELINA. 



the turnip formed by Ocyptera brassicaria. Another 

 species (Didectyum zigzag, Biley) preys on Phora aletige, 

 a parasite of the American cotton worm, Aletia argil- 

 lacea. 



The generic arrangement of the Eucoelina is a work 

 of great difficulty, chiefly owing to their great struc- 

 tural diversity to the difficulty of deciding whether 

 those variations in structure are of generic or merely 

 of specific value. Foerster has gone on the former 

 assumption, and has created a very large number of 

 so-called genera. I am hardly prepared to follow him 

 in his views. Take for example the antennae. For 

 the Eucoelidinse with incised wings (Kledotoma) he 

 formed five genera on the number of joints in the 

 antennal club for those with 7, 6, 5, 4, and3-jointed 

 clubs, so that if species would be discovered with a 

 one or a two-jointed club two additional genera would 

 be needed ; while as K. melanopoda has no club at all 

 a " genus " will have to be erected for its reception. 

 Further, the males in all these groups show no differ- 

 ence, the antennal form being alike in all. The line of 

 demarcation is rendered still more perplexing by some 

 of the species (as in the five- jointed section) having 

 the basal joint of the club but slightly thicker than the 

 preceding, so that they stand midway between two of 

 the " genera," as do some species of Pentatoma. Pre- 

 cisely the same reasoning applies to Eucoela, where we 

 find a complete bridging by intermediate forms of the 

 variously- jointed antennal club between an antenna 

 with no club and between those with abruptly three 

 to nine- jointed clubs. For these reasons I cannot look 

 upon the antennaB as furnishing a reliable character of 

 generic value. The only features afforded by the 

 wings upon which I feel inclined to place reliance are 

 the incision at the apex in Kledotoma f and in the radial 

 cellule being closed or open. It is certain that the 

 incision in some species is slight ; but still when we 

 find it, slight as it may be, combined with other pecu- 

 liarities, some value must be placed upon it. Also the 



