﻿118 CLEMENS' SYNOPSIS OF 



spiritrompe, proboscis, is a long, cylindrical transversely ribbed tube, consisting of two 

 symmetrical parts joined together by means of the serration of their edges, thus 

 forming a central canal. Each of these filiform portions contains also a canal in the 

 interior, which is a continuation of the oesophagus, so that the spiral tongue is fur- 

 nished with two separated, suctorial tubes. Hence, at the base of the tongue the 

 oesophagus is furcate, but subsequently a single tube is formed, the partition at the 

 commencement soon disappearing, and is continued thus to the stomach. The cen- 

 tral canal formed by the union of the two filaments has no suctorial function, but 

 the salivary vessels open into it at the base and discharge in it their secretion. The 

 oesophageal canals of the filaments, are placed in the midst of what I believe muscular 

 tissue, but I was unable to detect transverse striations in it under a power of 400 

 diameters. This tissue, which nearly fills the interior of the filaments, appears to 

 consist of two principal bands, one of which is attached to the upper, and the other 

 to the under surface of the interior, and regulate the extension and coiling of the fila. 

 ments, although this latter action is due mainly to the peculiar construction of the 

 corneous tube. The canal itself terminates in the bulb of the filament at an external 

 orifice, which I think I have seen distinctly in the bulb of the tongue of Macrosila 

 quinquemaculata. In this insect the bulb is corneous exteriorly ; but on the interior 

 surface it is very apparent, and is covered by an extremely delicate coat, having a few 

 scattered papillae, and is filled — at least in the dried specimen softened by macera- 

 tion — with a colorless gelatinous substance in which I failed to recognize any charac-' 

 teristic appearance. In Spilosoma acrcea, the filaments contain much less chitine 

 than those of the Sphinges, and the tongue makes a very good object for microscopic 

 examination without dissection. The filaments, however, have no terminal bulb, but 

 are flattened and very abundantly supplied with papillae on their inferior face. Next 

 the central canal within each filament, is found the spiral trachea. It is naked 

 as it is usually seen in the body, but is provided with an investing tunic {M. 5-maculata), 

 and gives off numerous branches from its outer side to the tissues surrounding the 

 suctorial canal, diminishing in size toward the bulb until it becomes impossible to 

 follow it, and ascertain how it is there distributed. It has no relation whatever to 

 the act of suction. This is performed by the sucking stomach, which lies almost con- 

 nected with the true stomach on the tract of the oesophagus, and by its expansion 

 the nectarous juices of flowers are pumped up through the suctorial canals. The 

 function of taste, I think beyond doubt, resides in the extremity of the filaments. 

 This is indicated not only by its structure, but we would expect from analogy to find 

 it there. 



At each side of the base of the tongue will be found a corneous process (fig. 3, 

 mx. p.) which is the external maxillary palpus, and the representative of the organ 

 we saw in a condition of high development in the larva. The internal maxillary 



