CONSTITUTION AND DEVELOPMENT OF TERMITES. 63 



distinct striatiou iudicative of secondary fibrillation is entirely 

 wanting. 



The fibres of the web cross in every direction^ but those of 

 the securing threads are more or less regularly parallel. 



The Embia, when moving in its gallery, bends up 

 the apical joint of the hinder pairs of tarsi, in order 

 that the claws may not come into contact with the 

 silk, and thus progresses without entangling itself. 

 This explains the physiological function of the 

 papillae I have described on the second and third 

 joints of these tarsi; it is by means of them that the 

 feet come into contact with the gallery. 



The silk is probably extruded as a liquid, and its structure 

 and the method in which the insect works lead me to 

 conclude that it is secreted in the anterior legs, which, 

 as will be seen farther on, are furnished with strongly de- 

 veloped glands. 



As an additional proof of so unusual and unexpected a 

 source for the silk, I made the following experiment. 



Ten intact Embiae were put into a glass vessel, and ten 

 more, whose anterior legs had been very carefully cut off, into 

 a similar one. The unmutilated examples all began to pro- 

 duce silk in half an hour to an hour, and had completed and 

 were comfortably living in their galleries at the end of twelve 

 or fifteen hours. The amputated Embiee lived and managed 

 to hide themselves between particles of earth, but produced no 

 silk. If the silk issued from the head, as one would tiieoreti- 

 cally suppose, some threads at least should have been found 

 in spite of the amputation.^ 



* [The translator Las kept examples of the Trinidad Embia urichi alive in 

 England for some time. Unfortunately they were sluggish, and would not 

 feed on anything that could be procured for them, but the little that was 

 observed of their web-producing methods was in accordance with Prof. 

 Grassi's account. Mr. J. H. Hart, E.L.S., by whose courtesy the specimens 

 were obtained, was incredulous as to this origin for the silk, but though he 

 observed the species under more favorable conditions he has communicated 

 no facts antagonistic to Prof. Grassi's observations. It may be added that 

 the salivary glands of £. urichi are apparently far too small to produce the 



