Editing Beetle (section)

===Circulatory system===
Like other insects, beetles have [[open circulatory system]]s, based on [[hemolymph]] rather than blood. As in other insects, a segmented tube-like heart is attached to the dorsal wall of the [[circulatory system#Nonhuman|hemocoel]]. It has paired inlets or ''ostia'' at intervals down its length, and circulates the hemolymph from the main cavity of the haemocoel and out through the anterior cavity in the head.<ref>{{cite book |last=Miller |first=T. A. |editor1=Kerkut, G. A. |editor2=Gilbert, L. I. |title=Comprehensive Insect Physiology, Biochemistry and Pharmacology. Volume 3: Integument, Respiration and Circulation |publisher=Pergamom Press |date=1985 |pages=289–355 |chapter=Chapter 8: Structure and Physiology of the Circulatory System |isbn=978-0-08-030804-3}}</ref>