284 FIRST A^STNUAL REPORT OF THE STATE ENTOMOLOGIST. 



Nature of the Egg-covering. 



The egg-covering of this insect is, in all probability, a special secre- 

 tion, deposited and arranged in such manner as may best serve for a 

 protective covering to the eggs. The insect has not, to our knowledge, 

 been observed in the act of constructing it, nor are similar coverings, 

 so far as we know, provided by other members of the Membracidm for 

 a like purpose, such as the Buffalo tree-hopper — Ceresa btcbalus 

 (Fabr.), the one-striped tree-hopper — TJielia univittata (Harr.), the 

 thorn-bush tree-hopper — Thelia cratcsgi Fitch, the unadorned tree- 

 hopper — Smilia inorjiata (Say), or the unarmed tree-hopper — Stido- 

 ccijliaVus 'i7ie7'mis (Fahr.), — all common species in the State of New 

 York. The egg-deposits of some of these have been described, but no 

 mention is made of any covering protecting them. 



The appearance and touch of the egg-covering of ^. binotata are so 

 decidedly waxy, that it was but natural to believe that such was their 

 character, for many of the insects belonging to the order of Hemiptera 

 are known to secrete wax to such an extent that it is collected and 

 utilized. Of the Fulgoridce — a family next in place to the Membra- 

 ciclcB, Westwood says: "The species of this family emit the white waxy 

 secretion in some cases to a remarkable extent. It is either cottony, 

 or arranged in lamell?e, and is evidently analogous to the wax secre- 

 tion of bees " {Introcluc. Class. Insects, ii, p. 429). Some of the Coccidce 

 — an allied family — are also wax secretors. One of the species pro- 

 duces, fi'om numerous secretory sacs or follicles, lodged just beneath 

 the skin of the abdomen, the important article of commerce known as 

 " Chinese wax," " vegetable wax," " vegetable spermaceti," or " pela." 

 In the American Naturalist, v, 1871, pp. 083-685, maybe found an in- 

 teresting account of its production. 



The material of the egg-covering of the two-marked tree-hopper* is 

 found not to be of a waxy nature. Some pieces of the Celastrus vine 

 bearing the masses were submitted to Dr. Hagen, and he has given 

 me the result of his examination as follows : " The curious white cover 

 consists of strings about 0.20 mm thick, which are composed of small 

 bubbles or cells of about 0.016 mm diameter. A portion placed on a 

 slide and brought over a lamp did not melt, but grew black, like coal, 

 proving it not to be wax. When boiled with water it assumed a milky 

 appearance, and the bubbles or cells disappeared. It is therefore simi- 



*The "two-marked tree-hopper," as designated by Dr. Fitch, is preferable for the com- 

 mon name of this insect, that it may not be confounded with the two-spotted tree-hopper, 

 Thelia himaculata Fabr. 



