38 PROCEEDINGS OF THE ACADEMY OF [1879. 



indeed show the appearance of such growth, which, however, is 

 only what might have been expected under such environment. 

 The belief was expressed that the ants fed upon the juices of the 

 leaves. But (if investigations in progress shall succeed) it was 

 hoped that the subject of the true food of the cutting ant would 

 be hereafter solved. 



5. Tunnelled Track*. The ability of these emmet masons to 

 excavate vast halls and subterranean avenues is remarkable. 

 Several holes in the vicinity of Austin were visited, out of which 

 "beds" or nests of ants had been dug, by an old man who used 

 to follow the business of ant killing. These holes were nearly as 

 large as the cellar for a small house. One such excavation, about 

 three miles from Austin, was 12 feet in diameter and 15 feet deep. 

 At the lowest point had been found the main cavity, quite as 

 large as a flour barrel, in which were found many winged insects, 

 males and females, and quantities of larvae. This nest was situ- 

 ated 669 feet from a tree that stood in the front yard of a house 

 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 line. 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 aver- 

 age, however, being about 18 inches. At the exit hole the tunnel 

 was 2 feet from the surface. The digging operations were de- 

 scribed, 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 larvae. The minims are quite ferocious 

 in attack, and gallantly support the large headed soldiers. 



6. Origin of Cades 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 evolution hypothesis 

 has encountered. Dr. Darwin, with that candor wdiich always 

 wins him the respect and confidence of all sincere minded oppo- 

 nents, fully admits this, and endeavors at some length to meet it. 

 The knot of the difficulty 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 modi- 

 fications had occurred in the workers, how, on the principle of 

 natural selection and hereditary transmission could these operate 

 upon such workers? All modifications of structure must be 

 wrought and transmitted through the female alone, effecting thus 



