12 U.S. NATIONAL MUSEUM BULLETIN 2 79 



ment of these larvae was checked periodically. It was found that the 

 development was retarded, however, whenever the larvae were dis- 

 turbed. Also, larvae left in the jars developed more rapidly than those 

 placed in the salve boxes. All rearings were carried out at room 

 temperature. 



Preparation and Study of Specimens 



A binocular stereomicroscope with an ocular micrometer was used 

 for the head capsule measurements. All measurements were made on 

 specimens submerged in alcohol. The greatest width of the head cap- 

 sule was usually found to be at the eyespots or just posterior to the 

 eyespots. The measurements are presented under each species descrip- 

 tion with LI indicating first stage larva, LII indicating second stage 

 larva, and LIII indicating third stage larva. The majority of the 

 descriptive work ^vas done using a binocular stereomicroscope and 

 magnifications of 10 X to 90 X. A binocular compound microscope 

 was used to observe the details of structures such as the macrosensilla 

 and antennal sensory pegs at magnifications of lOOX and 430 X. 



Permanent whole mount slides of the antennae, hypopharynx, 

 epipharynx, and maxillae were made for all species. The dissected 

 structures usually were mounted directly from 70-percent ethyl alco- 

 hol into Hoyer's mounting medium. Three small pieces of modeling 

 clay were placed about the mounting medium in a triangle, and the 

 cover slip placed on top of them. Pressure was then carefully applied to 

 the cover slip until the clay particles were flattened to a level where 

 the cover slip was in close contact with the mounted material. Heavily 

 pigmented or sclerotized structures were partially cleared in a solution 

 of hot, 10-percent KOH. These structures were removed to 70-percent 

 ethyl alcohol for several hours before mounting in Hoyer's. 



Formula for Hoyer's Mounting Medium 



50 grams distilled water 



30 grams gum arable (clear crystals) 



200 grams cliloral hydrate 



20 grams glycerin 



The ingredients should be mixed at 



room temperatui'e in the above sequence. 



It is unfortunate that many characters of taxonomic importance are 

 located on the mouthparts of scarabaeid larvae since these areas are 

 subject to considerable abrasion. The reader is cautioned to take into 

 consideration the fact that these structures may be broken, ground 

 down, or otherwise damaged in specimens of any instar which have 



