LECTURES ON EMBRYOLOGY. 



61 



condition of jaws, I say*, is of higher structure than 

 Chat which is observed in Crustacea; and affords 

 an additional evidence than Insects should stand 

 above Crustacea, To show this to be the case, let 

 me first answer a question. What are these jaws 

 in Insects ? By most difficult and extensive com- 

 parison, it has been ascertained that the iaws are 

 simply modified legs, and that there are all possi- 

 ble transitions to be observed in the various fami- 

 lies, between their ordinary legs and that peculiar 

 kind of moving appendages which perform, the 

 function of jaws, but which are so exceedingly dif- 

 ferent, owing to the great eminence in form to 

 which they arrive. 



Now in Crustacea, the changes which take place 

 between the appendages functioning as legs, and 

 those functioning as jaws, are so slight as scarcely 

 "Jo present any difficulty in ascertaining their com- 

 mon nature ; the differences are much less plain in 

 Insects, with their different sorts of jaws. You 

 scarcely can find the combining thread, showing 

 that in Insects there is one, and an uniform modi- 

 fication of appendages in legs and jaws. But com- 

 pare, on the ether hand,various appendages of the 

 Crustacea, and it strikes t us at once that they are 

 the same thing, slightly modified. 



Before I illustrate this point, let me remark, that 

 on looking at this diagram, there is scarcely any 

 one who would suspect that these figures represent 

 any thing more than the various claws which are 

 observed on the side of the lobster. And so it is ; 

 but nevertheless, some are :jaws, others claws, oth- 

 ers tins; the jaws being somewhat modified legs; so 

 that those parts are only a little diversified among 

 each other. We have something left of uniformity; 

 while we rise in Insects to the greatest possible di- 

 versity, and even a diversity which presents an 

 analogy with the character of concentration, ob- 

 served ia the various arrangements of their nerv- 



ous system, compared with that of Crustacea, So 

 that here we have another, and perhaps one of the 

 best, indications, that Insects stand higher than 

 Crustacea, notwithstanding we have the anatomi- 

 cal evidence to the contrary, which has been relied 

 on. Now if upon these data we should attempt a 

 classification of the class of Insects, let me in a 

 very few words make it clear. 



Insects have generally been divided into chew* 

 ing and sucking Insects, and then into other fami- 

 lies. Spiders have been separated as a class, and 

 also all Apterous Insects. 



Now, the Millipedes rank lowest, as among In- 

 sects they represeat the form of Caterpillars or 

 Worms, Next the Spiders, in which the concen- 

 tration takes place, in which the head and thorax 

 are distinct from the abdomen, bat in which head 

 and thorax are not separate, as in other insects 

 indicating some analogy to Crustacea. Then, we 

 would have those in which head, chest and abdo- 

 men are separated, but among them, place those 

 in which there are chewing jaws lower ; and high- 

 est the sucking insects. And curious it is, among 

 those which chew their food, that we have the less 

 perfect metamorphoses and many which are 

 aquatic in their larval condition; also among 

 them the forms are less perfect, inasmuch as in 

 Neuropterous insects the parts of the thorax are 

 only partially united, and the number of joints 

 remain greater even in the perfect insect i while in 

 the sucking insect, the parts of the thorax unites in 

 one mass, distinct from the head. In the Butter- 

 fly, we have, the evidence in the earliest lar- 

 val condition, that the Worm is an aerial animal, 

 rising above the other insects. And with these 

 data I think I have shown that I am not wrong in 

 considering the Insects as highest, if we judg 

 upon entomological grounds and not upon other 

 evidence. 



LECTURE VIII, 



i hoped to introduce another subject, which is 

 connected with the history and metamorphoses of 

 Insects ; but my time is so short that I scarcely 

 dare to mention it, only as connected with these 

 investigations. I mean, the singular peculiarities 

 of many insects who live in large communities s con- 

 sisting of individuals of different kinds, combined 

 in various numeric proportions, among which 

 there are not only Male and Female, but also an- 

 other kind of individuals, differing from them, 

 called Neuters. In those communities, individ- 

 uals live in various combinations ; there being, for 



8 



instance,m a bee hive, one Female, a Queen, as she 

 is called, a few hundred Males, and thousands of 

 Neuters, living together in one community. The 

 proportions are somewhat different in other spe- 

 ciesthe Wasps, Bumblebees, &c. &c. 



These facts, which are well known to Entomol- 

 ogists, and all those who have become acquainted 

 with the growth and education of Bees, show that 

 the ideas which are generally entertained about 

 the specific distinctions and the characteristics of 

 species, are not altogether correct. 



It is not throughout the Animal Kingdom that 



