440 Transactions. — Zoology. 



is covered with great numbers of very small simple circular 

 spinneret-orifices, but these do not extend to the median 

 dorsal regions. There is no fringe, properly speaking, but 

 all the organs just described produce secretion, as noticed 

 presently. Vasiform orifice rather broader than long, the 

 anterior edge slightly concave, the posterior edge broadly 

 convex ; operculum small, coverhig about one-third of the 

 orifice, with both edges concave, the anterior very deeply, the 

 posterior less, depressed ; lingula very long, extending some 

 distance from the orifice, roundly conical, v\'ith two rather 

 long setae near its end. 



The spinneret tubes and orifices above mentioned secrete a 

 large quantity of snow-white waxy threads closely felted, and 

 also, scattered amongst these, several long straight glassy 

 rods, which are very brittle ; these rods, when closely ex- 

 amined, are seen to be very delicately fluted. The threads 

 appear to be produced from the very numerous mmute spin- 

 nerets, and the rods from the rows of larger tubes. It results 

 from the absence of small spinnerets on the median dorsal 

 regions that the pupa-case in those parts is uncovered ; con- 

 sequently, it appears as if lying on a thick ring or cushion of 

 cotton, from which fact I have derived its specific name. 



On turning over the pupa-case and dissolving the waxy 

 matter, the rudimentary feet and antennae are clearly visible ; 

 the feet are thick and short, the antennae rather long, slender, 

 and in the latest stage numerously ringed. 



Adult form unknown ; but from the appearance of the 

 rudimentary wings in a late pupa examined, which was almost 

 on the point of emerging when it died, I believe that the fore- 

 wings will be dark and banded witli dark-brown, or perhaps 

 black. 



Hah. In Trinidad, West Indies. My specimens were sent 

 by Mr. F. W. Urich. I think the plant is Jatropha sp. 



It has been necessary to be particular in describing and 

 figuring the detads of spinnerets, &c., in this species, on 

 account of its similarity in some respects to three West Indian 

 insects: Aleurodicus anome, Douglas and Morgan; A. cocois, 

 Curtis ; and A. ornatus, Cockerell. I have already, in my 

 introductory remarks, mentioned that these and other authors 

 employ frequently the term "larva" to denote indiscrimi- 

 nately what I take to be both the larval and the pupal states. 

 Now, first, as to colour : the "larva " of A. anor.oi is said to 

 be "ochreous " ; that of A. cocois (as far as I can make out) is 

 similar; that of A. ornatus is "grey." No author mentions 

 dark longitudinal brown bands, such as those which are so 

 conspicuous in A. pulvmata. What is much more important, 

 in A. aiLonce Mr. Morgan gives fourteen " lateral infundibuli- 

 form compound spinnerets " and " secreting glands" ; A. cocois 



