INTRODUCTORY REMARKS. 47 



Linneus, as observed before, thought of dividing 

 the class into two orders, * Aculeo miti, ** Aculeo 

 punctorio. I have been stung, however, pretty 

 severely by one of those Ichneumons whose aculeus 

 is recondite, which genus is placed in the first, and 

 on the other hand, many insects which are put into 

 the second, are perfectly harmless in this respect ; 

 for instance, the aculeus of Chrysis is flexile and 

 can make no puncture. In fact, the term piinc- 

 toriiis, when applied to the aculeus of these in- 

 sects, must be regarded as relative, implying, not 

 that it can make no puncture at all, but merely 

 that it cannot penetrate the skin of the human 

 body, for all can make a puncture in such sub- 

 stances as are proper to receive their eggs. The 

 tibici of Hymen op terous insects are armed with 

 minute spines, from the variations of which, it is 

 possible characters might be drawn for good orders 

 in this class. Thus, for instance, the tips of all 

 the tibice in Tenthredo are armed with two spines ; 

 in Ichneumon, the anterior have one only, and the 

 others two ; in Apis, the two posterior have two, 

 and the four anterior one ; and in Formica all the 

 tibice are armed with a single spine only. These 

 distinctions, I believe, have not before been noticed, 

 but whether such orders would be natural or arti- 

 ficial, I am not prepared to say. 



From this account of the origin, progress, and 

 present state of the Hymenoptcra class, it will ap- 

 pear sufficiently evident, that though the class 



itself 



