THE AMERICAN ENTOMOLOGIST. 



59 



AN UNRECORDED HABIT IN THE LIFE-HISTORY 

 OF CERTAIN TRICHOPTEROUS INSECTS. 



Mr. Salvin recently placed in my hands 

 three leaves of hazel, upon each of which 

 was a gelatinous mass, enveloping either 

 ova or recently hatched larvae of some Tri- 

 chopterous insect ; the bushes upon which 

 they were found were situated at a consid- 

 erable distance from the nearest stream. 

 The ova in the still undeveloped mass were 

 arranged in regular series, made still more 

 evident by the two black eye-spots of each 

 embryo, which showed both through the 

 eggs and through the viscid surroundings. 

 After the lapse of about twenty-four hours, 

 the previously unhafched larvae were roam- 

 ing in their transparent environment, and 

 some of those already hatched had left it, 

 and were wandering about the box, prob- 

 ably in search of the element they were not 

 destined to find, and their size had won- 

 derfully increased since they were hatched. 



Only a few days before this experience, 

 Mr. Rye informed me that poplar leaves 

 bearing similar gelatinous masses had come 

 under his notice. This reminded me that 

 Prof. Westwood had once either recorded, 

 or mentioned to me verbally, quite a paral- 

 lel case (I now believe it was a verbal com- 

 munication) ; the accumulation of evidence 

 appears worthy of notice in a more promi- 

 nent manner. 



The size of the gelatinous masses was 

 considerable ; undoubtedly large at the time 

 of deposition, and increased by the absorp- 

 tion of moisture from the air. The juven- 

 ile larvae appeared to me to belong to the 

 Family Littuiophilidce, and, considering the 

 time of year, I have little doubt they per- 

 tain to the genus Halesus, all the conditions 

 agreeing therewith. 



These observations open up more than one 

 interesting problem in the early life-history 

 of Trichopterous larvae. Halesus is a genus 

 the larvae of which frequent streams. The 

 larvae hatched from the egg-masses collected 

 by Mr. Salvin would have had to travel 

 many yards before they reached the near- 

 est stream, or water of any kind, save that 

 resulting from recent rains. Furthermore, 

 it appears to me that the gelatinous secre- 



tion in which the eggs are enveloped may 

 serve as food for the young larvae, other- 

 wise it is difficult to account for the very 

 considerable increase in size of those I had 

 under observation, amounting in less than 

 two days to about double that of the newly 

 emerged larvae. 



All Trichoptera (so far as is known) void 

 their eggs in a viscid surrounding. Most 

 of them deposit this mass in the water or 

 on water plants. In the case now under 

 consideration it appears probable that cer- 

 tain of them prefer (either habitually, or 

 casually) to avert immediate contact with 

 the element in which their progeny must 

 eventually pass the greater part of their 

 lives, and to trust to chance that some of 

 them may, at the proper time, reach their 

 aquatic home. 



There is mystery about the infantine life 

 of most Trichopterous larvae, notwithstand- 

 ing that it was from observations on the 

 eggs of a species of this Order that Baddach, 

 in 1854, wrote a memoir that contributed 

 greatly to the advancement of embryology 

 in insects, a subject that of late years has 

 become almost a distinct branch of natural 

 science. — R. McLachlan, in Entom. Monthly 

 Mag. (London^ Nov. 1879. 



INSECTS INJURING THE BLACK LOCUST 



{Robinia psendacacid). 



BY V. T. CHAMBERS, COVINGTON, KY. 



Farmers in Northern Kentucky are mak- 

 ing many complaints about the injury that 

 is being done to locust trees by insects. 

 The principal depredators are the beetle 

 Hispa {Uroplata) suturalis Fabr., both as 

 larva and imago, and the Tineid larvae of 

 Lithocolletis ornatella Cham., Lithocolletis 

 robiniella Clem, and Gracilaria {Parec- 

 topd) robiniella Clem. Many other insects 

 feed also on the Locust ; and it sometimes 

 happens that a species which has been 

 usually not very abundant, will suddenly 

 become so numerous and commit such 

 devastation as to become for the time a 

 plague. For this reason I deem it best to 

 refer briefly to the other insects which feed 

 on the Locust, before referring further to the 

 principal depredators above named. Thus 



