THE CONCHUELA. 53 
tabla 14 by tabla 15 (which was planted in corn), showed on July 29 
an average of between 2 and 3 adult conchuelas for each 100 plants. 
No actual estimates of the numbers of the insects present had been 
previously made, but from casual observation it is practically certain 
that the general decrease in numbers had occurred on this tabla as 
well as on the others examined. Other observations in various places 
confirm the belief that the diminution in the numbers of the insects 
occurred generally throughout the plantation. Messrs. J. P. Conduit 
and J. A. Vaughan informed the writer that after August 1 the bugs 
never appeared anywhere on the plantation in what seemed de- 
structive abundance, although a few were constantly present in va- 
rious sections. During the first week in December, no frost having 
occurred, the author could find no specimens of the conchuelas in the 
cotton fields, although within two weeks a live specimen had been 
seen at the gin, having been accidentally brought in with seed 
cotton. 
The seasonal history at Barstow, Tex., in 1905, showed a similar 
record to that at Tlahualilo. The conchuela there was very abundant 
about the middle of July, and, while by no means uncommon on 
August 11 and 12, it was evident that a considerable reduction in 
numbers had taken place during the previous 2 or 3 weeks. On 
September 12 it was found that only a slight further reduction in 
the number of adults had taken place, but nymphs were compara- 
tively scarcer. A month later Mr. J. C. Crawford, of the Bureau 
of Entomology, found that nymphs in the fourth and fifth instars 
were much more abundant than they had been on the dates of the 
two preceding examinations; the adults were slightly more abundant 
than on September 12, and mostly soft, indicating that they had 
recently matured. On November 14 Mr. Crawford, in a few hours' 
search where the bugs had previously been abundant, could find no 
nymphs and only a half dozen adults, all of which had attained the 
ordinary degree of firmness and were therefore not recently matured 
as were those collected on the preceding visit. 
HIBERNATION. 
The conchuela appears to hibernate exclusively in the adult stage. 
Observations have been recorded under the subject o{ duration 
of the nymphal stages which indicate that it is highly improbable 
that immature forms ever survive even one-half of the winter season. 
No field observations have been made upon the hibernation o( this 
species owing to the fact that as cold weather approached the sur- 
viving adults were so scarce, even where they had been previously 
most abundant, that to obtain positive results more attention than 
it has been practicable to give would have been required. Nineteen 
