48 REPORT 



the same essential peculiarities of minute structure as were described 

 by Minot* in the orthoptera. The lining epithelium is thrown up into 

 folds so as to form imperfectly differentiated glandular follicles. If the 

 epithelium be brushed off, the characteristic arrangement of the mus- 

 cular fibers can be seen, Plate VI, Fig. 7. There is an internal coat, com- 

 posed of a great number of pale fibers running transversely around 

 the stomach and more or less parallel to one another. Outside are the 

 longitudinal striped muscles, which are distributed in single bundles, 

 1 1, and do not form a continuous layer. Each bundle is composed of 

 a number of fibers and pursues its own course ; the bundles are not 

 l)arallel, but sometimes two bundles unite, or are connected by a third; 

 their general trend is longitudinal. Finally it must be mentioned 

 that numerous tracheal branches i)enetrate the muscular layers, and 

 ramify through both them and the connective tissue. 



EXTERNAL ANATOMY OF THE EVIAGO. 



To prepare the external skeleton for examination the following method 

 is satisfactory and convenient. The whole insect, either in the fresh 

 state or after preservation in alcohol, is placed in a test tube with a solu- 

 tion of caustic potash and carefully boiled over a flame for a couple of 

 minutes. The specimen is then thoroughly washed with water, to which 

 a little acetic acid or vinegar is added to neutralize the alkali. The 

 specimen while in this state may be brushed with a camePs-hair pencil, 

 and most of the scales removed. It is best to put it next, for twenty- 

 four hours, in strong alcohol and to then complete the brushing upon 

 the hardened object. With a little care and x)atience aU the hairs and 

 scales can be removed without injuring the crust. 



A view of the exoskeleton of the female is given on Plate VIII, Fig. 1. 

 We shall follow Mr. Burgess' memoir upon the Milkweed Butterfly,! as 

 to the homologies and nomenclature of the parts. The head is more 

 triangulrtr in outline, when seen from the side, than in Banais, and the 

 eyes,^, are relatively" smaller. The palpi and maxillje are very similar 

 to those of the butterfly. The antennae, «, are thicker and the enlarge- 

 ment of the two basal joints is quite marked. The thorax is large and 

 compact. The first segment (I) is small, the second (II) by far the 

 largest of the three. The prothorax is connected with the head by a 

 narrow neck, which is perhaps really the anterior portion of the first 

 thoracic segment. This point is better shown in a view of the underside, 

 Plate IX, Fig. 1. The front legs are there removed; the insertion of 

 coxre into the thorax is shown at P ; just in front of this insertion is a 

 thickened ring of hard crust ; farther forwards the integument is mem- 

 branous, and the prothorax proper becomes directly continuous with 



* MiBOt, C. S. Histology of the locust ( Caloptenus) : and the cricket (Anabrus) : Chapter X, in Second 

 Keport of the United States Entomological Commission. 1880. Pp. 1 83-224. Plates II- Vm. 



t Btirgesa, Edward. Contributions to the Anatomy of the Milkweed Butterfly {Banais archippus^ 

 Fabr.). Anniv. Mem. Boston Soc. Nat. Hist. 1881. 



