INTRODUCTION. 59 



some authors as absorbents. From having observed 

 them chiefly in long and slender trunks, Reaumur 

 was led to conceive, that their only use is to render 

 that organ more steady, by affording numerous points 

 of support, and adhering in some degree to the sub- 

 stances into which it is inserted; an explanation 

 rendered highly probable by the fact, that the long 

 and slender ovipositors of Ichneumons, and many 

 other insects, are generally provided with some point- 

 ed projections near the tip, evidently intended for 

 this purpose. Several of the figures on Plate I. are 

 designed to illustrate the structure of the organ just 

 described. Fig. 9, is a magnified view of the trunk, 

 showing its general form, and the projecting points 

 near the tip (a). Fig. 10, is a highly magnified sec- 

 tion, exhibiting the two portions (a, b) of which it is 

 composed, each of them tubular (d, d), and forming 

 by their junction a central canal (e). Fig. 11, is 

 another section, representing the under side. 



The two portions of which the proboscis is com- 

 posed, seem to be analogous to the maxillae or un- 

 der jaws of the mandibulated tribes, and to receive 

 their great development at the expense of the other 

 oral appendages, most of which are small and incon- 

 spicuous. This is not the case, however, with the 

 labial palpi, which are generally of considerable size, 

 and curved upwards in such a manner as to form two 

 projecting points in front of the head. These or- 

 gans are covered with hair-like scales, are usually of 

 a somewhat conical shape, and consist, for the most 

 part, of three articulations. (See PL I. fig. 12, a 



