208 



PSYCHE. 



[June, 1901 



Holonisia rubiginosa, are found abun- 

 dantly in a slime composed of decaying 

 leaves and soil and water on the banks 

 of Adalanta Creek near this University 

 (Stanford). The larva is so large, full- 

 grown specimens averaging about 2 to 

 2J inches in length, and the character 

 and disposition of its internal organs so 

 readily and certainly made out in dis- 

 section, that it is chosen as subject for a 

 short study of internal insect anatomy. 

 As Holonisia does not occur elsewhere 

 in the United States than on the Pacific 

 Coast (as far as is known) students in 

 other regions will have to use the larva 

 of some other Tipulid species. Some 

 rather large Tipulid is common in almost 

 every locality, and the use of another 

 species than the one whose structure is 

 here described will make the work to 

 some extent comparative in character 

 and thus be even more instructive and 

 interesting than if the same subject 

 could be * used. The account of Holo- 

 7-usia will be found to answer as a guide 

 to the dissection of any other Tipulid 

 larva. 



External Anatomy (Fig. A). 



Technical note. Bring a number of the 

 larvae of some large Tipulid species 

 (found in vegetable slime, or about grass 

 roots in pastures, etc.) alive into the 

 laboratory. Note tlie various motions 

 and the locomotion of the body. Kill 



* I shall be glad to send to any one, two specimens of 

 Holorusia larvae, properly killed for dissection, if the 

 postage and actual cost of the wooden mailing bottles, 

 amounting to about (?) cents, are paid by tile applicant. 



specimens by dropping into boiling water. 

 After the specimen has straightened out 

 and stiffened, requiring about a minute, 

 (death is almost instantaneous) remove 

 to 30% alcohol. After two or three 

 hours remove to 50% alcohol, and after 

 three hours into 70% alcohol. After 

 twelve to twenty-four hours remove to 

 85% alcohol, in which keep the speci- 

 mens. 



[Verify the following statements if 

 Holonisia is used ; if another Tipulid 

 is used compare conditions with those 

 here described.] The ' body is com- 

 posed of thirteen segments. Retracted 

 into the first and second segments is the 

 head., with strongly chitinized capsule. 

 At the anterior end of the head, usually 

 projecting slightly, are the short cylin- 

 drical unsegmented antennae and the 

 strongly chitinized biting mouthparts. 

 ( The mouthparts can be better ex- 

 amined after the internal anatomy has 

 been studied and the retracted head 

 wholly exposed.) 



The hindmost body segment bears 

 terminally on a flat surface two large 

 dark spiracles (breathing openings) sur- 

 rounded by six backward projecting 

 flexible lobes. On the ventral surface 

 of this segment is the anal opening of 

 the alimentary canal, on an elevation 

 bearing four large and two smaller flex- 

 ible processes. The segments of the 

 hinder half of the body have each a 

 median transverse construction ; those 

 of the anterior half are difficult to dis- 

 tinguish from one another, but it is 

 assumed that each pair of the lateral 



