Nov. 5, 1931 Biology of Embaphion muricatum 331 



Sterna more or less dull, finely and not distinctly sculptured. 



Parapletirse smooth, rather sparsely but not very distinctly punctate. 



Abdomen horizontal, very finely and sparsely punctulate, obsoletely rugulose and 

 quite evenly convex. 



Legs rather slender, moderate in length. Anterior femora mutic, pro tibial spurs 

 similar in the sexes, the anterior slightly longer than the posterior. Protarsi simple. 



LIFE HISTORY AND DEVELOPMENT 



The principal observations on the hfe history and development of 

 Embaphion muricatum, as given below, were made under laboratory and 

 field conditions in south-central Kansas, at an altitude of approximately 

 1,200 feet. Under different conditions of latitude, altitude, and humidity 

 there would doubtless be found more or less marked variations. The rec- 

 ords are unfortunately based on incomplete studies for, owing to working 

 conditions and to pressure of other duties, there was no opportunity to 

 conduct a sufficiently extensive series of experiments to render all obser- 

 vations conclusive. 



The eggs are deposited in loose, dry, or slightly moist soil at a depth 

 of ^ to I inch, sometimes singly, but more often in clusters of two or 

 three to a dozen or more eggs at one place. At temperatures ranging 

 from 80° to 90° F. the average period of incubation is approximately 

 10 days, whereas at temperature's of 68° to 70° F. the egg stage is approxi- 

 mately 13 days. Undoubtedly weather conditions and the time of year 

 have a direct bearing on the duration of the egg period. 



During the later stages of development and shortly before hatching, 

 the surface of the egg becomes light brown in color, and the shell appears 

 to expand slightly and to become more flexible, while the movements of 

 the young larva can be noted within. During the process of hatching, 

 the struggles and the lifting pressure of the young larva burst the shell 

 and the larva emerges by rather slow periodic movements, as its integu- 

 ment is very soft and fragile. Though the young larva often remains 

 for some time near the place of hatching, yet it is capable of locomotion 

 soon after emergence. All normal eggs of the same egg cluster usually 

 hatch within a short period, generally a few hom-s. While abnormal 

 weather conditions may prolong the period of hatching, no injurious 

 effects of such retardation are noted in the eggs. No infertile eggs were 

 ever collected under field conditions. Soon after the emergence of the 

 larvae the empty eggshells become more and more contracted and dried 

 up, until eventually only tiny, shrivelled fragments remain. 



Upon hatching the larva averages 3.5 to 3.75 mm. in length and is 

 yellowish white. The color changes sHghtly after each molt until at 

 maturity the larva becomes a deep yellow. 



The length of the larva stage, according to an experiment consisting of 

 3 1 larvae hatched in June and kept in a cool cellar at an average tempera- 

 ture of 68° F., averaged for the siu-vivors 79 days, while in an experiment 

 consisting of 49 larvse, under similar conditions, it varied from 76 to 



