148 NATURAL SCIENCE [September 
(should they care to do so), if the Government or the County 
Councils would take up the question officially and systematically. 
But such a work would involve much original research. 
AMERICAN Economic ENTOMOLOGY 
WE have also received from the U.S. Department of Agriculture 
a short but interesting pamphlet by Mr C. L. Marlott on “ Insect 
Control in California.” The well-known plan of introducing lady- 
bird beetles to prey upon the imported scale-insects which 
devastate the western fruit-orchards has been successfully extended ; 
while an efficient artificial insecticide has been found in hydrocyanic 
acid gas with which the trees are fumigated after being covered with 
a temporary canvas tent. Mr F. H. Chittenden writes on the 
European Asparagus beetles which, ike so many old-world insects, 
have been introduced into the Atlantic States. Dr L. D. Howard 
gives an illustrated account of various portable steam pumping- 
engines used for spraying trees with insecticide fluids. 
GLANDS IN INSECTS 
In the latest part of the Zvransactions of the Entomological 
Society of London (1897, pp. 113-126, pt. v.), Mr Oswald H. Latter 
describes the structure and function of the sternal gland found in 
the prothorax of the caterpillar of the “ Puss” moth (Cerwra vinula). 
The formic acid secreted by this gland has long been recognised 
as a defence to the larva against its enemies. Mr Latter has now 
shown that at the end of larval lfe the secretion has another 
function. Mixed with the silk the acid serves to make the cocoon 
which contains the pupa exceedingly hard and waterproof as well as 
strongly adherent to foreign substances such as the chips of wood 
which this caterpillar habitually works into its cocoon, 
Mr Latter points out that in other lepidoptera and insects 
of different orders, many segments of the body possess glands which 
may reasonably be considered serially homologous with that under 
consideration ; he suggests that all these glands represent the coxal 
glands of arachnids. The prothoracic gland of C. vinula opens into 
a shallow vestibule, whence arise branched eversible tubes bearing 
groups of spines in their cavities. Mr Latter is unable to suggest a 
satisfactory function for these tubes, but he points out that the 
groups of spines recall the parapodial setae of chaetopods, and that 
the whole structure supports Mr Bernard’s view that such glands 
are derived from the acicular gland sacs of ringed worms. Should 
these relationships prove to be correct, Mr Latter believes that they 
“will go far towards establishing the primitive nature of the cruci- 
form larva of which many observers are already in favour.” 
