folsom: mouth-parts of orchesella cincta. 9 



reference rather to their systematic value than to their anatomical de- 

 tail. His accurate description, relating mainly to skeletal structures, is 

 of great value. 



Fernald ('90, '90 a ) maintained that the so called " salivary glands " of 

 Anurida maritima opened into what Tullberg named the linea ventralis, 

 a median ventral groove terminating in the ventral tube. 



Willem and Sabbe ('97) accept the results of Fernald, and infer that 

 the well known exudation from the ventral tube is secreted by the large 

 cephalic glands, which had been regarded as salivary in nature. 



Upon the whole, our present knowledge of the mouth-parts of Collem- 

 bola is fragmentary and far from complete ; it is indeed insignificant, 

 compared with what is known of the mouth-parts of most other orders 

 of insects. The physiological side of the subject is practically untouched. 



Methods. 



The mouth-parts of Orchesella cincta 1 were studied from dissections 

 supplemented by serial sections. Dissections were necessarily made 

 with needle-knives under dissecting or compound microscopes. First, 

 the chitinous skeletons were prepared from alcoholic or fresh material 

 by separating the mouth-parts in water and treating them with potassic 

 hydrate. The immediate muscular attachments were then studied from 

 dissections in water, weak alcohol, or glycerine, permanent preparations 

 being made in glycerine. The normal relations of the mouth-parts were 

 ascertained by rendering the entire head gradually transparent by weak 

 potassic hydrate. At a certain stage in the process, the mouth-parts 

 become prominent, owing to the pink or purple color they acquire from 

 the solution and diffusion of the ectodermal pigment they contain. 

 The stain thus obtained is permanent in glycerine or balsam dissolved 

 in xylol. 



For killing and fixing, preparatory to sectioning, the principal agents 

 used were either hot water, hot alcohol, hot corrosive sublimate, or picro- 

 sulphuric acid. Hot water or hot alcohol was as good as anything, caus- 

 ing a well relaxed condition ; some of my best preparations were killed in 

 hot alcohol of seventy per cent. Embedding was most conveniently per- 



1 The species used in this research has hitherto been called Orchesella flavo- 

 picta Pack. ; it is, however, synonymous with the European O. cincta L., as I have 

 ascertained by comparing Packard's types, which are preserved in the Museum of 

 Comparative Zoology, with examples of the latter species given to me by Dr. C. 

 Sehaffer of Hamburg, by whom they were identified. 



