114 N. E. McINDOO 



been poor ones, for he did not see any of the internal structures, 

 nevertheless he called them sense organs, even though he did not 

 observe their innervation. Since they look like pits from a super- 

 ficial view, he called them ''Gruben ohne Kegel" to distinguish 

 them from similar pits bearing minute hairs. Since he failed to 

 understand their internal structure, he did not speculate on their 

 function. 



During the past ygar the present writer has collected and 

 fixed material belonging to three species of Lepidoptera. A few 

 specimens of each one of these species have been examined, but 

 few olfactory pores have been found. Fortunately five coleop- 

 terous larvae belonging to the 'fig-eater' , Allorhina (Cotinis) nitida 

 L., were also collected; two of these were fixed in Carnoy's fluid 

 and the other three were treated with caustic potash to remove 

 all the soft tissues. Immediately after examining the integu- 

 ment of these larvae, it was observed that olfactory pores are 

 quite abundant on all the appendages, and since they were 

 easily found in sections, it was decided to use the larva of this 

 species as a type before collecting more material in order to make 

 a comparative study of these organs in the larvae belonging to the 

 different orders of insects. 



The larvae of Allorhina feed mostly upon the roots of grass, 

 but sometimes they attack the roots of strawberries and other 

 plants. The food of certain other larvae varies widely, while 

 that of the silkworm is restricted to mulberry and osage-orange 

 tree leaves. Since all larvae are more or less selective in regard 

 to then food, it would seem that they have sense organs to per- 

 ceive the food. The sense organs of larvae have been studied 

 little in comparison to those of adult insects. The ocelli cannot 

 see sufficiently well to distinguish differences between objects 

 of the same size, because, while experimenting with the larvae 

 of Dytiscus marginalis in water, Nagel (1894) asserts that these 

 larvae always grabbed pieces of meat and filter paper; they 

 immediately ate the meat but invariably released the filter paper. 

 Nagel thought that they distinguished the meat from the paper 

 by the sense of taste which he says is brought about by means 

 of minute hairs (known as olfactory pegs), located at the tips of 



