A. S. Packard, Jr. on certain Entomological Speculations. 217 



nida, and of the larva to the Myriapods, also denied by Mr. Walsh, is 

 grounded on the same principles as the Class resemblances, and need 

 not detain us here. 



Tn fact there is a common, typical, worm-like form, of which all ar- 

 ticulates, whether they be Insects or Crustacea, Myriapods or Arachni- 

 <la. are but simply a modification. All degraded Articulates, all embryos 

 of the Insecta and Crustacea tend at first to assume a general cylindri- 

 cal, elongate form, be its length twice, or thrice, or quadruple the width 

 of the body. 



Of the female degraded Bopyridae, Mr. Spence Bate, the eminent En- 

 glish Careinologist. states that they "diverge to so large a degree that 

 in Entoniscus and Cryptoniscus they would, but for the character of 

 their larvae, be mistaken for Planarise or Annelids."* 



Fritz Midler in his Work entitled " Fur Darwin," as stated by Mr. 

 Bate, speaks of the " worm-like larval skin " of some Isopoda. The 

 degraded female Sacculina and Peltogaster, so closely related to the 

 Cirrepedia, are strikingly like some Planar ians and Nemerteans. 



Both the biregional form of the Crustacean with its cephalothorax 

 and abdomeu, and the triregional cephalized Insect with its head dif- 

 ferentiated from the posterior part of the body, are but a more special 

 working out of the archetypal worm-like form. 



With these principles of the classification of Articulates in view, we 

 might have been spared such short-sighted and shallow criticism as ap- 

 pears in the pages under review. 



Agaiu, Mr. Walsh calls in question a statement made by us"f" that the 

 dipterous genus Laphria, by reason of its plump, hirsute body resem- 

 bles a Bombus. objecting that all the species of Laphria are not plump 

 and bee-like. We fail to see the force of the objection. It is sufficient 

 for our purpose, and quite obvious to observers generally, that certain 

 species of Laphria resemble the Humble Bee. By a strange mishap 

 Mr. Walsh derives from our remarks just the idea we wished to con- 

 vey: i. e. that certain exceptional Diptera, that is, those forms among 

 the least characteristic of the sub-order, copy the Bombus-form, but 

 th.it neither do all the Diptera, nor all the species of Laphria, ever ne- 

 cessarily imitate the Humble Bee. 



Our author truly remarks that all the species of Bombus are not yel- 

 low and black, but that some are "red and black." and also that some 

 Laphriae are likewise "red and black" as well as "fulvous and 



Guntlier's Zoological Review for 1864, p. 267. 

 fOii Synthetic Types in Insects. Bust. Journ. Xat. Hist., vol. 7, 1863, p. 580. 



PROI EEDtNGS ENT. SOC. PHILAD. NOVEMBER, 1866. 



