ZOOLOQY AND BOTANY, MICROSCOPY, ETC. 729 



Structure of the Stigmata of Insects.* — Dr. O. Kranclier, who 

 has already published a preliminary account of his investigations,! 

 here enters into a very elaborate description. After some histo- 

 rical remarks he proceeds to a general account of the organs in 

 question, of the substance of which we have already given an abstract. 

 He then gives a list of the forms he has examined and enters into a 

 detailed description of their peculiarities. As a general result he 

 finds that the variation both in the structure and form of the stigmata 

 is unexpectedly large. No systematic generalizations can be drawn 

 from the study of these, but, in proportion as their value diminishes, 

 the greater importance do we give to the influence of adaptation on 

 their structure. 



The following has been the author's method of investigation — 

 when he had only to do with the connection between the several 

 chitinous parts, the portions to be examined were treated with a 

 10 per cent, solution of potash, the water was then removed by 

 alcohol, the object clarified by oil of cloves and set up in Canada 

 balsam. When the muscle was sought for, the whole object was 

 first coloured by a solution of picrocarmine. Sections were also 

 made after imbedding in paraffin ; soap was found to be of no use as 

 an imbedding material. 



Origin of the Tracheal System of Insects. | — Dr. H. A. Hagen 

 is unable to agree to some of the views of Dr. Palmeu on this subject, 

 and is himself of opinion that the so-called stigmatic cords are not 

 rudimentary and closed tubes, but useless open ones ; he points out 

 that in ^sclma, for example, the tracheal system is not closed, and 

 he reminds his readers of the experiment of Lyonet, who, by placing a 

 larva in water, and then heating the water, found that air-bubbles 

 escaped from it. Dr. Hagen has, with satisfactory results, repeated 

 this experiment. This would seem to strike at the root of Dr. 

 Palmen's principal position, that the stigmatic cords do not become 

 completely developed during the larval stages. 



Endocranium and Maxillary Suspensorinm of the Bee.§ — 



Professor G. Macloskie has published a paper in which the anatomy 

 of these parts of the honey-bee is very fully and elaborately dealt 

 with, comparing them with their representatives in a few other 

 insects. The paper itself must be referred to as it is not capable of 

 being usefully abstracted. 



The author complains that " anatomists have not paid much 

 attention to this class of structures, and some eminent students of 

 insect embryology are as silent regarding the endoskeleton as if they 

 had never heard of such parts, although all efforts to evolve an insect's 

 embryology ought to include as a preliminary study the structure of 

 its internal economy." 



He considers as the result of his observations that they indicate a 



* Zeitschr. f. wiss. Zool., xssv. (18S1) pp. 505-74 (2 pis.). 



t See this Journal, ante, p. 34. 



X Zool. Anzeig., iv. (ISSl) pp. 404-6. 



§ Amer. Natural., xv. (18S1) pp. 353-62 (6 figs.). 



