THE CANADIAN ENTOMOLOGIST. 



are pretty regularly arranged, and sometimes lie flat on the cylinder (pro- 

 bably when they have just emerged from the opening, or are about to 

 return), sometimes stand out in a threatening manner. But it is on the 

 summit that these tentacles are most numerous, piled up, lying one upon 

 another and in all directions, so that it is impossible to count them. The 

 caterpillar has the power of protruding these organs at its will, either one 

 alone or both together. It throws them out like the tentacles of Papilio 

 or the horns of snails. Sometimes it shows but half their length, and 

 then the tentacles expand but little or none at all ; sometimes it projects 

 them fully, making the tentacles radiate in all directions. Most often it 

 allows itself to be handled, tickled, pricked, without exposing them, which 

 seems to exclude the idea that these organs are means of defence or of 

 intimidation. . . . The observer will readily cause them to appear by 

 pressing the larva from head to anus. 



" But this is not all, and our caterpillar presents another singularity. 

 At the summit of the ioth segment" (/. e., nth, counting the head as 

 first) " is found still another opening, this time unique, placed transversely 

 and surrounded by a raised pad, about which the granulations which cover 

 the body of the caterpillar become particularly dense. From the middle 

 of this opening (boutonniere, button-hole), comes forth, at the will of the 

 caterpillar, a sort of transparent, hemispherical vesicle, which gives escape 

 to a fluid sufficiently abundant to form a good' sized drop, which repro- 

 duces itself when it is absorbed. The caterpillar only secretes this fluid 

 when it is disturbed, imitating in this respect ciicullia and many other 

 larvae which disgorge by the mouth a colored fluid, doubtless with the 

 intention of driving away their enemies. As to the end which nature 

 proposes by this exceptional structure, it is not easy to divine it. The 

 explanations which one has imagined in some analogous circumstances 

 appear to me too forced that I should expose myself in risking new 

 ones." The figures illustrating this- description represent a cylindrical 

 tube, bulbous toward the summit, and bristling with feathery-looking 

 tentacles. This corresponds with Mr. Lintner's description of '"'barbed 

 spines,'' and with a pen and ink sketch which he also sent me. But he 

 represented the tube as wholly cylindrical, not at all bulbous, and there 

 is probably a specific difference in this respect. 



I learned from Mr. E. T. Ciesson, to whom I had mentioned the facts 

 observed in June, that Rev. H. C. McCook, of Philadelphia, had seen 

 something of the same nature, and I wrote Mr. McCook to inquire. He 



