1894.] MICROSCOriCAL JOUllNAJ.. 59 



tioiis of head, antenna', pal[)i and taivsi, the more impor- 

 tant parts being- illustrated in the accompanying figure 

 of Dooophorn.s adapted from Piaget, (Z/e.s- Pedionliiie.s. 

 Supplement Plate 17.) The abbreviations are as follows : 

 01. dypeus, sc. clypeal signature, bi. internal band, ba. 

 antennal band, tr. trabecula, a. antenna, o. eye, ni. man- 

 dible, ob. ocular band, pi. labial palpus, 1. labium, oc. b. 

 occipital band, os. occipital signature, icb.intercoxal baud, 

 pro. prothorax, met. metathorax, cox. coxa, tro. trochan- 

 ter, fem. femur, tb. tibia, ong. onglets, lb. lateral band, 

 sp. spiracle, gs. genital spots, v. vulva. 



In another paper may be given a key to the species 

 found on our common animals for the convenience of 

 those wishing to determine their finds. The writer will 

 be pleased also to determine specimens sent him for the 

 purpose. 



A Homogeneous Objective Condenser. 



By WILLIAM LIGHTON, 



OMAHA, NEBK. 



The attention of the microscopist is now more than ever 

 engrossed with the important part borne by the condenser 

 in contributing to satisfactory results of his work. A 

 good condenser is now no more a mere adjunct : it is a 

 necessity. For many years I have been experimenting 

 in this direction, with results which I wish here to par- 

 tially outline. 



In The Microscope for October 1891, I described sonic 

 of the effects obtained by the use of a homogeneous im- 

 mersion objective as a sub-stage condenser. That was 

 but the beginning. I have since carried forward experi- 

 ments looking toward the perfection of a homogeneous 

 immersion condenser, and with the valuable aid of one of 

 England's best opticians have attained the desired result. 

 I have now before rpe the first instrument constructed ot\ 



