4 Ins. xm. INSECTA. [1905] 
gives (1371) a very interesting sketch of the tracheal system, including the 
anal structures, of a developing Libellulid dragon fly. 
Of two papers on the sense organs, the one by Rohler (1288) deals 
with the subject in general, and contains much interesting matter, while 
that by Seiler (1375) discusses the Ocelli of Epheineridce. Both touch 
also on the question of function, though rather lightly. Phillipps con- 
tributes a valuable paper on the compound eye (1 164). Popovici-Baznosanu 
(1211) has studied the structure of the dorsal vessel in Chironomus and a 
few other insects. RIdl (1230) has an interesting discussion of the sense 
of hearing. 
Fabre’s new volume (533) is chiefly devoted to spiders, but it includes 
two short chapters on Cocddce. Buttel-Reepen has an article on Insect- 
sociology (224). We owe to Doflein a most interesting account of the 
proceedings of (Ecophylla smaragdina , the weaver-ant (436), while Huber’s 
account (791) of the mode of establishing a colony in the case of the leaf- 
cutting ants is quite fascinating. The origin of slavery in ants is discussed 
at length by Wheeler (1619) and Wasmann (1579, 1580). Ferton gives 
us some valuable notes on the habits of Hymenoptera ; the case of para- 
sitism in a Pompilus being of special interest (558). Some very interesting 
information as to the Natural History of a Singhalese species of Termitidce 
is given by Doflein (437). Dr Goeldi has published a very considerable 
contribution to the Natural History of Brazilian mosquitoes (672). 
Gross (699) has written on the ovaries of Mallophaga and Anoplura y 
and finds them to be extremely similar. He discusses the classification of 
these groups, and concludes that there is but little ground for placing 
Anoplura with Hemiptera. 
Bordage has produced a very interesting treatise on autotomy and 
regeneration (135), and Thienemann (1491) makes an important con- 
tribution by his sketch of the biology of the pupa of Trichoptera, and 
accompanies it with a very complete bibliographic list. 
Silvestri gives a preliminary account (1393) of an extraordinary case 
of germinogony, accompanied by larval, dimorphism. Heymons (745) 
gives a brief sketch of the peculiar embryology of Machilis. Miss Fielde 
(559) contributes a valuable set of observations on the progeny of virgin — - 
chiefly worker — ants. 
Miss Stevens (1449) gives us a number of interesting observations as 
to the veiy earliest processes of ontogeny in those extraordinary creatures 
Aphidce. 
In Variation we have an important memoir from Enteman on the 
colour and pattern of Polistes (518). Pictet has given the results of his 
experiments as to the variation produced by changing the food of Lepi- 
dopterous larvae (1198). He experimented with 4 or 5000 individuals of 
21 species of Swiss Lepidoptera. The part of his work relating to humidity 
is less conclusive. 
The memoir by Petersen (1155) on the sexual organs, requires careful 
consideration from all Lepidopterists, as ho is far from considering previous 
work exhaustive, and makes various suggestions having a very wide 
bearing. He also has a paper (1156) to exemplify his views as to the origin 
of species by physiological isolation, by the case of Hadena adusta ; the 
variation of the male genitalia being illustrated by photographs. 
Jordan’s work (822) should be read in conjunction with Petersen’s ; 
he discusses geographical and nongeographical variation. The two works 
emphasise the necessity of a thorough study of the variation of sexual 
organs, both writers apparently taking it for granted, that disparity in the 
copulatory organs prevents copulation. A hypothesis which is by no 
means established, though the assumption is far from new. 
The most remarkable of the Economic work of the year, is the series 
produced as Report of the Hawaiian Sugar Planters’ Association by 
