no N. M. Stevens 



two heterochromosomes are always found between the two polar 

 masses of chromatin separating like any other unequal pair. In 

 the telophase and youngest spermatids they are usually still sepa- 

 rate from the general mass of chromatin (Fig. io8). An abund- 

 ance of material for further study of this form is much to be 

 desired. 



The chromosomes of Coptocycla clavata are very similar to those 

 of Coptocycla guttata (Nowlin '06). There are eighteen in the 

 spermatogonium, the two smallest being the unequal pair of hetero- 

 chromosomes. The testes of Lina laponica were examined with 

 the hope that there might be some perceptible difference in chro- 

 mosomes corresponding to the dimorphism described by Miss 

 McCracken ('06) but none was found. The first spermatocytes 

 contain seventeen rather small bivalents, one of which is quite 

 unequal, and the second equatorial plates show clearly the usual 

 dimorphism. 



MISCELLANEOUS 



A number of the Coccinellidae have been found to have nineteen 

 large and one small chromosome in the spermatogonia and ten in 

 the spermatocytes as in Adalia bipunctata ('06, PI. XIII, Figs. 

 193 to 197). An unequal pair has also been found in one of the 

 Rhynchophora, Phytonomius punctata, and in Obera tripunctata, 

 one of the Lamiinae. 



DISCUSSION 



The character of the heterochromosomes has now been deter- 

 mined for more than fifty species of Coleoptera, belonging to 

 sixteen families. In twelve species an unpaired heterochromo- 

 some has been found, in all of the others an unequal pair, and in 

 Diabrotica soror and Diabrotica 12-punctata ('08) from one to 

 four small supernumerary heterochromosomes may be present 

 in addition to a large unpaired one. 



In connection with the work on the odd chromosome in the 

 Coleoptera, new material of Stenopelmatus ('05) has been studied, 

 and the spermatogonial number determined as forty-seven instead 

 of forty-six. It was also possible to count one cyst of second 



