852 



SCIENCE 



[N. S. Vol. XXXVIII. No. 989 



color vision, it is exactly an even blue-green, 

 ■which looks to the yellow-blue visioned individ- 

 ual achromatic. In this case, of course, there 

 was no occasion for trying blue-green,. since the 

 rats could not be shown to have any color 

 sense at all — a result which there are several 

 reasons for having anticipated. Nevertheless, 

 it remains true — ^what v. Frisch's discovery 

 confirms— that you can not, as a matter of 

 fact (nor in my theory), draw simple infer- 

 ences from the unitary colors to the color- 

 blends. 



Professor v. Prisch has sent me specimens 

 of the blue-gre€ns to the chroma-quality of 

 which his bees are insensitive ; I should be glad 

 to share them with any one who can proceed 

 to test the blue-green sense of any animals 

 which are already known to be blind to red. 

 Christine Ladd-Franklin 



Columbia IjNrvEESiTT, 

 November 7, 1913 



NOTES ON A CHESTNUT-TREE INSECT 



While in the employ of the Pennsylvania 

 Chestnut Tree Blight Commission, last win- 

 ter, my attention was called to numerous bur- 

 rows almost always present in the bark of the 

 chestnut tree, particularly in the smooth- 

 barked trees. These are the burrows that 

 Metcalf and Collins referred to in the U. S. 

 Farmers' Bulletin, No. 467, as the work of 

 Agrilus hilineatus. As we were sure the bur- 

 rows were not made by this species, the com- 

 mission force referred to the insect maker as 

 the Bast Miner. Not much was accomplished 

 on the study of this insect until the spring 

 season advanced. Then much effort was di- 

 rected to the solving of the life-history of this 

 insect and what relation it bore to Endothia 

 parasitica. When the work stopped in July, 

 the life-history was nearing completion, and 

 a number of experiments were in progress 

 which would have given some interesting re- 

 sults. A detailed account of the description 

 of the larva and its work, etc., was prepared 

 for publication, but the only adult obtained 

 was injured irreparably and probably can not 

 be named. Because the adult insect emerged 

 after July 1 (the time of my leaving Penn- 



sylvania), it has been impossible to work out 

 the egg-laying habits. The larvae hibernate 

 in the burrows in either the second or third 

 instar. During the winter months they are 

 inactive, but, as soon as spring opens, activity 

 commences. When finished, the burrow is not 

 very extensive, the longest not being more than 

 six inches and extending longitudinally. In 

 width, it extends only over a very short dis- 

 tance. 



While the insect is living within the trees, 

 the burrow can not be detected externally. 

 After the emergence of the larvae, however, 

 the bark swells over the burrow, often crack- 

 ing and making a conspicuous wound. The 

 larvse leave the trees during the first part of 

 June through minute exit holes, dropping to 

 the soil, in which they spin a seed-pod-like 

 cocoon, characteristic of some of the Micro- 

 lepidoptera. 



Under insectary conditions, the adult insect 

 emerges during August. The injured speci- 

 men was sent to Mr. W. D. Kearfott, but of 

 course could not be named. 



The number of exit holes made by these in- 

 sect larvae is enormous in any given area of 

 chestnut forest and as these holes are made 

 just at the time of year that the blight spores 

 are very abundant, and conditions generally 

 are favorable for their development, it is be- 

 lieved that this species of insect has an im- 

 portant bearing upon the spread of Endothia 

 parasitica. 



A. G. Euggles 



University op Minnesota, 

 November 10, 1913 



a connecting type? 



An illustration of how completely a student 

 may become confused in a written examina- 

 tion is shown in the accompanying figure, 

 which is an exact tracing, somewhat reduced, 

 of the figure drawn by a freshman in an ex- 

 amination in elementary zoology. 



The question was to make a sketch, from 

 memory, of course, of the anatomy of Amphi- 

 oxus, as seen in lateral view. 



At first glance the sketch appears to be a 

 fairly good representation of a lateral view of 



