December, '11] webster: insects of 191i in iowa 525 



in northern Iowa it seems probable that other counties are equally as 

 well infested with the oyster-shell scale as Worth county. 



All of the samples of this scale which have been sent in to the 

 Experiment station in recent years have come from the northern half 

 of the state. The scale occurs in southern Iowa, but rarely, and when 

 it is found, the infestation is light. I am not sure what is the cause 

 for this difference, but think likely that it is on account of more favor- 

 able conditions for the development of certain natural enemies of the 

 scale. This is probably especially true of certain mites, concerning 

 which I shall have more to say at another time. 



Monostegia ignota Norton. This strawberry slug, or at any rate 

 the species which has gone under this name, was very common in 

 strawberry patches about Ames early in the spring. In one instance 

 strawberry plants in a small field were practically eaten down to 

 the ground by these slugs. 



According to F. W. Mally there are in Iowa two common species 

 of strawberry slugs. ^ These are quite similar and are doubtless often 

 taken for a single species. In making some notes on these strawberry 

 slugs this spring Mally's observations were found to be essentially 

 correct. The second species of strawberry slug, HarpipJiorus macidatus 

 Norton, is fairly common in Iowa, although the first named species 

 has been causing the more damage. This is probably due to the fact 

 that the former species appears earlier in the spring, when the straw- 

 berry plants are smaller and less resistant to insect injury. 



Meliana albilinea Hiibner. The wheat-head army-worm, which 

 caused much damage to timothy in northern Iowa last year, was prac- 

 tically lost sight of this year. Early in June it looked as if much 

 injury would be done, since the partly grown larvie were very common 

 in many places. The continued long period of dry weather, however, 

 completely dried out the timothy plants and heads, as well as other 

 grasses, and the larvae were left without suitable food The drought 

 checked the wheat-head army-worms as well as the timothy. 



Epitrix cucumeris Harris. The potato flea-beetle was again abun- 

 dant in Iowa this year. Around Ames much injury to the tubers was 

 noticed, as well as to the foliage. The tunneling into the tubers was 

 found to be essentially as described by F. C. Stewart as occurring in 

 New York State. - 



Eriocampoides limacina Retzius. The pear-slug was less abundant 

 at several places in the state where it has been common for several 

 years. This decrease in numbers seems to have been due, for the most 



1 Insect Life, vol. ii, p. 137. 



s N. Y. Agr. Exp. Sta. Bui. 113. 



