162 KANSAS UNIVERSITY SCIENCE BULLETIN. 



sibly representing the second anal vein, was found in one 

 specimen. 



6. The color pattern was found to consist of polygonal or 

 irregular groups of pigmented, disklike outgrowths of the 

 cuticula. The manner of producing the pattern is various. 



7. The male genitalia were found to consist of supra-anal 

 plate, subgenital plate, couplatory organ and forceps. 



8. The female genitalia consist of supra-anal plate (orna- 

 mented with a double row of wax glands, flask-shaped in longi- 

 tudinal section), subgenital plate and ovipositor. The ovi- 

 positor was found to be homologous in many points to a 

 hymenopterous ovipositor as seen in the honeybee (a sting). 

 Comparison with other homopterous forms showed it to be 

 homologous in most points with that of the cicada, but almost 

 identical to that of the Aleurodidse, showing, with the buccal 

 appendages, the close structural relationship of the Psyllidse 

 to that family. 



TECHNIQUE. 



My studies have been based upon dissections and serial sec- 

 tions. 



Dissections were made in three ways: (1) A dissecting 

 stand fitted with an 0.8-inch lens was used in some cases; (2) 

 some of my work was done under a compound microscope (one- 

 inch eye-piece and one-inch objective) on the lower end of 

 whose draw-tube was placed a three-inch objective, thus pro- 

 ducing an erect image. This combination was useful but its 

 disadvantage was that the eye was too far from the specimen 

 being dissected on the microscope stage; (3) the greater part 

 of my dissecting, however, was done under a "Pfeiffer's Erect- 

 vision Dissecting Microscope" using objectives three inch, one 

 inch and two-thirds inch. This was found to be the most con- 

 venient, especially in the more delicate dissections, such as of 

 mouth parts and genitalia. By the use of very fine, sharp- 

 pointed needles, these minute organs could be torn apart with 

 ease. 



Most of my material was boiled for a short time in caustic 

 potash, and then treated with alcohol and xylol previous to 

 dissections, no fresh specimens being available at the time 

 when this work was done. Xylol was of great use in clearing 

 the parts, but at the same time it rendered them brittle and 

 easily broken. 



Dissections were made under water, alcohol, xylol and glyc- 



