ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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tend to become internal head-structures. The ligula is rarely paired, 
may be rigid or flexible, and has closely associated with it the hypo- 
pharynx. The paraglossre are never jointed, and tend to become obso- 
lete. The labial palps are essentially tactile. From the most generalised 
type, found in the Blattidae, the modification is first from a divided to a 
single ligula ; next to a disappearance or obsolescence of the paraglossse ; 
later the labial palps also disappear, and finally the hypopharynx is dis- 
pensed with. 
As to the maxillte, the sclerites form three series, each of which has 
its own possibilities of development. The lacinia never develop except 
as chewing or piercing organs, the galea varies in the direction of form- 
ing an enveloping organ for all the other mouth-parts, and the subgalea 
eventually unites along one margin for that purpose. There is a ten- 
dency to develop a ridged membrane on the inner surface of the galear 
joints, which culminates in the pseudotrachea of the muscid labella. 
The palpifer has a small range of development, from an unjointed 
flexible tactile organ to a rigid piercing structure, and, as this becomes 
useless, to a process for the attachment of muscles used to flex the 
proboscis. 
Classification of Orthoptera.* * * § — M. L. Bordas divides Orthoptera 
into — (I.) Acolotasia, ivithout diverticula at the anterior end of the mid- 
gut (Phasmidee and Forficulidae), and (II.) Colotasia, with intestinal 
diverticula, more or less numerous (Blattidae, Mantidae, Acrididae,. 
Locustidae, and Gryllidae). The classification, primarily based on the 
absence or presence of caeca, is elaborated in reference to the number 
and arrangement of the Malpighian tubules, the structure of the giz- 
zard, &c. 
Development of Apterygota.f — Dr. B. Heymons has studied the 
development of Lepisma saccharina L. The segmentation is peripheral, 
not total, and an amnion and serosa are developed. Thus the Inseeta 
apterygota are not exclusively anamnia, as is usually said. At the same 
time, it must be noted that in Lejpisma the amnion-cavity is a large space 
between the blastoderm and the surface of the egg, and that there is no 
complete separation of amnion and serosa, an amnion pore being left. 
The antithesis between the Pterygota and the Apterygota is thus lessened 
by Lepisma and its relatives. 
Check-List of Coccidae.f — Mr. T. D. A. Cockerell points out that, 
there is at present, as the ‘ Zoological Record ’ shows, unusual activity 
among coccidologists. A check-list, complete to date, has been a deside- 
ratum, and this he has now supplied. In his list he ignores all £; nomina 
nuda ” (names without description), and separates off the “ nomina serni- 
nuda” (with inadequate description) from the “ nomina valida,” of which 
773 are recorded. 
Mosquito-Bite. § — Mr. E. S. Morse has an interesting letter in Nature 
on acquired immunity from mosquito-bite and insect stings. Mr. 
G. Macloskie, in the same number, describes the mosquito’s three pairs 
* Comptes Kendus, cxxiv. (1897) pp. 821-3. 
t SB. Akad. Wiss. Berlin, 1896, pp. 1385-9. 
X Bull. Illinois Lab. Nat. Hist., iv. (1896) pp. 318-39. 
§ Nature, lv. (1897) pp. 533-4. 
