544. 

 POLYCENTROPUS IRRORATUS. 



Order Trichoptera. Fam. Hydropsychidae. 



Type of the Genus, Philopotamus irroratus Curt. 

 PoLYCENTROPUS and Philopotamus Curt. — Hydropsyche Pictet. 



Antenna inserted in front of the crown close to the eyes, a little 

 longer than the body, rather stout and attenuated, composed of 

 numerous pubescent joints, the basal one very short and thick, 

 2nd quadrate, 3rd and 4th oblong, the remainder becoming gra- 

 dually slender, longer and oval (1, a few basal joints). 

 Maxillary Palpi long, incurved, pilose and 5-jointed in both 

 sexes, 2 basal joints short, the latter very pilose, 3rd long and 

 stout, 4th rather shorter, subclavate and furnished with strong 

 bristles on the inside as well as the 3rd joint ; 5th slender, as 

 long as the others united, wrinkled, giving it the appearance of 

 being composed of numerous cup-shaped joints, the apex ovate 

 (4). 



Mentum somewhat trilobed. Palpi considerably shorter than 

 the maxillary, pubescent, triarticulate, 2 basal joints very stout, 

 1st the shortest, somewhat obconic, 2nd truncated obliquely, 

 3rd longer than the other 2, but much slenderer, membranous, 

 a little dilated at the base and apparently composed of 12 or 13 

 joints, the apex ovate (5). 

 Head rather transverse ovate : eyes lateral and globose : ocelli undis- 

 covered. Thorax not broader than the head, and rather short. Ab- 

 domen short and narrow, the apex of the male furnished ivith 2 ovate 

 lobes beneath, and a process producing 2 divaricating appendages like 

 claws ; conical in the female. Wings defexed in repose, superior 

 with 6 furcate terminal nervures and 4 or 5 transverse ones (9) ; 

 mier'wr folded with S furcate marginal nervures. Legs, hinder pair 

 the longest : thighs, middle pair a little the longest : tibiae, anterior 

 short, with a spine on the side before the middle and 2 at the apex 

 (8); intermediate rather the stoutest, with 2 pair of long spurs, one 

 pair near to the base (*); posterior jjazV very long and slender, with 

 two pair of long spurs, one at the apex and another considerably be- 

 low the middle (f); tarsi long slender and 5-jointed, intermediate a 

 little dilated and compressed, as well as the apex of the tibia, parti- 

 cularly in the females ; claws and pulvilli small. 

 Larv'se living without a case : Pupae with a simple envelope. Pictet. 



Irroratus. — Curt. Guide, Gen. 75P. 



In the Author's Cabinet. 



The present genus is a proof of the necessity of minutely in- 

 vestigating these curious insects, for although at first sight they 

 bear a strong resemblance to the true Philopotami, they are 

 considerably diflPerent in structure : there are no less than 22 

 spurs on the legs, and the terminal joint in all the palpi is 

 very remarkable : in the labial especially it has so much the 



