352 ZOOLOGY 



INSECTS. 



SCOLOPENDRELLA, THE TYPE OF A NEW ORDER OF MYRIOPODS. 



The genus Scolopendrella has recently been reexamined by Mr. John 

 A. Ryder,* and he has found some remarkable peculiarities in its organi- 

 zation, which, in his opinion, entitle it to be differentiated as the "repre- 

 sentative of a distinct order of Myriopods. The characteristics^ accord- 

 ing to Mr. Ryder, " indicate as much affinity with insects as with myri- 

 opods, and may, indeed, be looked upon, perhaps, as representing the 

 last survival of the form from which insects may be sujiposed to have 

 descended." The head is essentially like that of a true insect, and the 

 epicranial pieces are distinguished by well-marked suture from the 

 labrum. The labrum and labium are both well defined; mandibles and 

 maxillae are developed, as well as, apparently, a ligula. The antennte 

 have numerous (14 to 28) articulations. The body proper has thirteen 

 segments. The legs (in number 12 or less) are five-jointed, and each 

 terminated by a pair of claws, as in the typical insects, and at the 

 bases of each pair, except the first, are attached simple hairy append- 

 ages. The genital orifice is on the ventral side, in the third or fourth 

 body segment, in both sexes. The tracheal system is represented by a 

 series of simjjle tubular arches, without a spiral filament, arising from 

 openings on the ventral surface inside the base of the legs. Of this 

 combination of characteristics not the least noteworthy are the biun- 

 guiculate legs, and their nearly complete correspondence in number 

 with the rudimentary abdominal and functional thoracic limbs of the 

 Thysanura, especially Machelis and Lepisma, which have also basal ap- 

 pendages to the legs; it is these characteristics that point to the afiinity 

 with Insects almost as intimate as that with the Myriopods. The order 

 thus distinguished has been named Symphyla, in reference to the singu- 

 lar combination of characters presented. It may be added that this 

 order has already been adopted by a special student of the Myriopods, 

 Latzel having accepted it in his lately published work on the Myrio- 

 pods of the Austro-Hungarian monarchy. Whether it will be hereafter 

 associated most intimately with the typical Mj^riopods or Insects, re- 

 mains to be seen ; but it is at any rate certain now that these two tyi^es 

 cannot be retained as full classes. 



INSECTS INJURIOUS TO BOOKS. 



Tlie question of injuries incurred by books from the attacks of insects 

 has been examined into by Dr. IIagen,f and Professor Westwcod. Repre- 

 sentatives of not less than six orders of Arthropods are more or less in- 

 jurious. 



Among the mites is the common Cheyletus eruditus, which attacks 

 paper in damp ijlaces. 



* Ryder ( Johu). Scolopendrella as the type of a new order of Articulates. Am. 

 Nat., vol. xiv, pp. 375, 376. 

 tHageu (H.). Attacks of Insects on Books. Jour. Boy. Micr. Soc, vol. iii, p. 422. 



