447 
Habits of the Cutting Ant of Texas. 
point had been formed the main cavity, cpiite as large as a 
flour-barrel, in which were found many winged insects, 
males and females, and quantities of larvae. This nest was 
situated G69 feet from a tree that stood in the front yard of a 
house and which the ants had stripped. Mr. McCook took the 
range of the underground way traversed by the ants to reach 
this point, from which an accurate route was constructed and 
exhibited. The course varied very little from a direct linp. 
Two branch tunnels were made to a peach-orchard 120 feet 
distant. Reference was made to a paper by Dr. Lincecum in 
the Proceedings of the Academy, which gave an account of 
the tunnelling of a stream by these ants. There is nothing 
improbable in this, as the tunnel above referred to went down 
in places as deep as 6 feet, the average, however, being about 
18 inches. At the exit hole the tunnel was 2 feet from the 
surface. The digging operations were described, in which 
the small forms alone seemed to take part. The large forms 
would therefore appear to assist in opening the gates, make 
the excursions, and do the cutting; the small forms to do the 
digging, or, at least, the carrying out of excavated earth; 
while the minims, or least forms, assist in opening and closing 
doors and keeping charge of the larvse. The minims are 
quite ferocious in attack, and gallantly support the large¬ 
headed soldiers. 
6. Origin of Castes by Evolution. —This wide differentiation 
of form among the insects of one species and nest is one of 
the most serious special difficulties which the English evolu¬ 
tion hypothesis has encountered. Mr. Darwin, with that 
candour which always wins him the respect and confidence 
of all sincere-minded opponents, fully admits this, and en¬ 
deavours at some length to meet it. The knot of the diffi¬ 
culty lies in the fact that the worker castes are sterile, and 
are produced from eggs laid at different periods by the female. 
Supposing, therefore, that profitable or other modifications 
had occurred in the workers, how, on the principle of natural 
selection anti hereditary transmission, could these operate 
upon such workers ? All modifications of structure must be 
wrought and transmitted through the female alone, affecting 
thus the worker-life enwrapped in the egg. But it ap¬ 
pears quite impossible to comprehend how any structural 
modifications could act from the worker upon the queen in 
order to thus react upon a succeeding generation of workers. 
The illustrations which Mr. Darwin cites the variation of 
domestic cattle by interbreeding, and M. Verlot’s experiments 
* ‘ Origin of Species,’ p. 227. 
