96 THE PERIODICAL CICADA. 
They are found in both wet and dry places; on the low and on the high ground; 
singly and in colonies of many thousands. One hut, even in a damp soil, may be 
surrounded by a dozen holes, from which the insects emerge without making any 
huts, and often where we may expect to find them they are never seen. 
Accepting the theory proposed by ^li\ Lander for the condition 
found to exist in the Nyack region, Doctor Love does not deem it 
entu'ely adequate, as he says: 
The huts are sometimes found in places in which the soil is of great depth and which 
are not especially exposed. Such was the case at Baychester, where only a few huts 
were found, and these in deep soil and so well protected that it was only after careful 
search that they were discovered. 
He offers the supplementary explanation that since it is hardly 
possible that the Cicada larvae can determine instinctively the dis- 
tance to be traveled in their upward journey nor the time required 
to accomplish it, which will vary with the nature of the soil to be 
tunneled and the directness of the line followed in theii* excavations, 
it may often happen that individuals reach the surface before they 
are prepared to assume the adult condition, and the number so doing 
would be greater when the conditions all united to favor a short 
passage. In protected localities where the soil is deep the larvae Mng 
near the surface will be more likely to emerge before their pupal 
changes are complete, and would thus be led to the construction of 
these cones. This, he says, would also explain theu' seeking tem- 
porary shelter, as they do, under logs and stones, as has been pre- 
viously noted. 
The explanation offered for the construction of the Cicada cones by 
Mr. Lander, as supplemented by Doctor Love, seems, on the whole, 
satisfactory and adequate, so far as the conditions studied by these 
wTiters are concerned. The conditions as described by ]Mi\ Rathvon 
do not inform us as to the natm-e of the soil, but both in the Rathvon 
case and the later instance described by Mr. Davis, the wet character 
of the ground would seem to indicate a soil of a considerable depth. 
This would seem to give a basis of reason for the explanation suggested 
by Mr. Rathvon and accepted by Professor Riley. A complete 
hypothesis, therefore, seems to be in a union of the explanations 
offered, namely, that the cone-building habit is induced either by a 
shallow soil, proximit}^ of the pupae to the sm-face, or conditions of 
unusual warmth which brings the pupae to the sm'face in advance 
of then normal time, and more rarely to unfavorable conditions of 
excessive moisture. The mud caps are to protect the burrow from 
cold until the time of issuing arrives. 
The explanation of the occmTence of these structures on hi^h 
gi-ound suggested by Professor Riley is certainly untenable. He 
surmised tliat the individuals constructing cones in such situations 
did so because impelled by habit that had become fixed and hered- 
