THE MALPIGHIAN VESSELS OF HALTICA 

 BIMARGINATA SAY (COLEOPTERA). 



By William Colcord Woods.* 



1. The general structure of the larval vessels. 



2. The general structure of the vessels of the imago. 



3. A comparison of the conditions in Haltica bimarginala with those described 



for certain other Coleoptera. 



4. The function of that portion of the tubes associated with the wall of the colon. 



1. THE GENERAL STRUCTURE OF THE LARVAL VESSELS. 



INTRODUCTION. 



In connection with a study of the internal metamorphosis 

 of the alder flea beetle, Haltica himarginata Say (Chrysomelidae), 

 a problem which has been occupying the attention of the writer 

 for some months past, observations have been made on the 

 number and arrangement of the Malpighian vessels in these 

 insects. Some striking features were brought out, which 

 seemed worthy of special mention. 



THE ALIMENTARY CANAL OF THE LARVA. 



In the aHmentary canal of the larva of the alder flea beetle, 

 the three primary divisions, fore-intestine, mid-intestine, and 

 hind-intestine can be made out readily. The fore-intestine 

 consists of a short pharynx, a short oesophagus, and a short, 

 thin-walled distensible crop. The mid-intestine, which forms 

 by far the greater part of the canal, is divided into two regions, 

 separated exteriorly by a constriction, each region having a 

 distinct type of epithelium pecuHar to it. The hind-intestine 

 consists of three short regions, a small intestine or ileum, a 

 large intestine or colon, and a very muscular rectum. The 

 distinction between these parts is clear as well in dissected 

 specimens as in sectioned material. 



Figure 1, a diagram of the aHmentary canal, shows the 

 relationship of these parts, although the intestine is actually 

 more convoluted and the folds overlie one another to a greater 

 extent than is there indicated. 



*Contribution from the Entomological Laboratory of Cornell University. 

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