1916] Malpighian Vessels of Haltica Bimarginata 399 



that organ; the thinner vessels are separately inserted. The 

 fixation at the rectum is made by two trunks of three vessels 

 as in the longicorns. " (Page 157). " Galeruca ta?iaceti * * * 

 have the four principal vessels inserted on the ventriculus by 

 a single very short stump (souche) which does not deserve 

 to be called a gall bladder, and fixed on the rectum by two well 

 distinct trunks. The thin walled vessels have isolated inser- 

 tions." (Page 158). On the same page the conditions are 

 described for G. lusitanica, the only difference being that here 

 the ventricular insertion of the four tubes of the first series 

 is not by a bladder, but separately. 



In a general way the conditions in Haltica agree with those 

 described by Dufour. His generalization (page 154) that in 

 tetramerous Coleoptera the posterior insertion is never uni- 

 cauline (by one trunk) as in the great majority of the hetero- 

 merous, but is bicauline (by two trunks) or fasciculated, holds 

 true for bimarginata, in which the bicauline condition exists. 

 In Crioceris, in Cassida, and in Galeruca there are two series 

 of vessels, a series of four large tubes, and a series of two smaller 

 more delicate vessels, just as is the case in the alder flea beetle. 

 In Donacia also, the two series of tubes can be recognized. 

 In most cases the four vessels of the first series empty through 

 a bladder (an urinary bladder of course and not a gall bladder) 

 and there is a colonic insertion of the tubes as occurs in Haltica 

 bimarginata. (Although Dufour always speaks of a rectal 

 insertion of the vessels, he used this term loosely ; and in reality 

 all of his figures show the Malpighian vessels passing very 

 clearly into the wall of the colon, or second division of the hind 

 intestine, and not into the rectum, or third division.) In 

 nearly every case which he figured, the vessels of the second 

 series are isolated in their ventricular insertion. 



The greatest differences appear when Haltica bimarginata 

 is compared with Donacia. In both cases there are two series 

 of vessels, the first series comprising four tubes, emptying 

 into the alimentary canal by a common bladder, and the second 

 comprising two shorter vessels with isolated insertions. In 

 the latter insect, the four vessels of the first series unite at their 

 distal ends, and it is for this reason that Dufour regarded them 

 as really only two vessels, and referred to them as handle-like 

 (vaisseaux a anses). The fusion of the vessels into two common 



