peters' handbook oe zoology. 33 



ters exist of sufficient value to justify the division of the Hetero- 

 cerous Lepidoptera into two sections, but in any classification 

 professing to show the natural affinities of these Insects, the Butter- 

 flies (Ehopalocera) may certainly claim to form a group of higher 

 rank than that of a family. The Diptera also are divided into sec- 

 tions on an unusual principle, — the true Diptera {Diptera genuina, 

 Gerst.), after the deduction of the Pupipara and Aphaniptera, being 

 formed into two groups, according as the pupa is coarctate or not. 

 The group with an obtected pupa includes the Tipuliform and Culi- 

 ciform families, with the Tdbani, Asili, Empidce, Bomhylii, and some 

 other families, — that with a coarctate pupa only the Mtiscidce, Si/r- 

 pliidce, and Stratiomyidce. The propriety of this mode of division 

 seems rather questionable ; tlie pupa in both sections is essentially 

 the same, and the circumstance of its being retained within the dried 

 larva-skin in the one set of forms and not in the other can hardly bo 

 regarded as of equal importance with the structural differences by 

 which the Nemocerous and Brachycerous Diptera are distinguished. 



Dr. Gerstaecker's seventh and last order of Insects, to which he 

 gives the name of Hemiptera, includes the Ehynchota of Burmei- 

 ster, with the addition, as stated above, of the Mallophaga. ^he 

 author refers the Ploteres to the Hydrocores, which is certainly 

 incorrect, but in other respects the classification adopted by him, 

 although not satisfactory, furnishes a good general view of the insects 

 composing this little known order. 



The treatment of the small class of Myriapoda presents nothing 

 to call for special notice, but in the classification of the Arachnoidea, 

 Dr. Gerstaecker departs widely from the principles ordinarily adopted 

 in the division of this class into groups. The old sections of Pul- 

 monary and Tracheary Arachnoids are entirely ignored by him, and 

 in place of them he adopts groups founded upon certain peculiarities 

 in the external structure. Thus his first order is denominated Arthro- 

 gastra, and includes all the Arachnoidea with '*a sessile and distinctly 

 segmented abdomen," whether they respire by means of lungs or by 

 tracheae. The groups thus brought together into a single order are 

 very heterogeneous in their character, including, as they do, the 

 Scorpions, Phrynidise, Pseudoscorpiones {Chelifer), Phalangida?, and 

 Solifugae (Solpuffa), — nay. Dr. Gerstaecker even interpolates the 

 Chelifers between the true Scorpions and the Phrynidae in his first 

 section of the order which he designates Didactyla, from the pre- 

 sence of didactyle nippers on the first maxillary palpi. "We cannot 



N.H.R.— 18C5. D 



