18G4.] • - 285 



'another vague analogy between the pupa or what he calls the Chrysalis 

 state of insects and the Crustacea. {Methods of Study, pp. 237, 312.) 

 But in Crustacea the head is soldered to the thorax without any suture, 

 while in the pupa of Lepidoptera, Hymenoptera, Coleoptera, Diptera 

 and the true Neuroptera, which even Agassiz does not assert to pass the 

 larval and pupal states in the egg, the head is connected with the tho- 

 rax by a very distinct connate suture, and in many Coleoptera, espe- 

 cially Tetramera, and most Hymenoptera and Neuroptera there is, in 

 addition, a very distinct constriction or neck at this suture, thus oflFer- 

 ing not even the faintest resemblance to the Crustacean Cephalothorax. 

 I say nothing of the other Orders or Suborders, where there exists a 

 perfectly free suture between the head and the thorax of the pupa, 

 because these are probably the very groups which Agassiz believes to 

 pass the larval and pupal states in the egg. In another passage an 

 analogy is traced between, on the one hand, the larva state of insects 

 and the elongated, worm-like Centipedes, (Myriapoda,) and, on the 

 other hand between the pupa state of insects and the spiders (Arach- 

 nida) with their head and thorax confluent as in the Crustaceans. 

 {Ibid. pp. 75-6 and compare p. 312.) To this last analogy there is 

 precisely the same fatal objection as to the first.* 



* There is a remarkable genus of ant-like spiders — whether described or not 

 I do not know, though it is not mentioned either by Latreille or Say — with a 

 very strong medial constriction in the thorax so as to apjjear to have a distinct 

 head. This seeming head is subquadrangular, and bears a small eye at each 

 of the four angles and on the depressed frontal surface two enormously large 

 ones, each nearly ^ as wide as the head, making six in all. But there is no 

 connate suture or free articulation whatever at the constriction, as I ascer- 

 tained from the recent specimen, and the front pair of legs arise from this 

 seeming head and not from the other part of the thorax. The posterior pair of 

 legs are much longer than the others, the other .3 pair alike in every respect. 

 The paljii are about i as long as the front legs, 3-jointed, each successive joint 

 slightly shorter than the preceding. The other parts of the mouth are small 

 and indistinct. If undescribed, this genus may be called Mj/rmecarachna, from 

 the great resemblance to the worker ant. In the Scorpion ide genus Chelifer, 

 also, of which I possess Ch. ohlongus Say, the thora.x is divided by two trans- 

 verse slightly indented lines into 3 portions, the anterior one of which bears 

 the eyes and the brachiform palpi and the otlier two portions the 4 pairs of 

 legs. 



