On Maggots and Murders: Forensic Entomology Editor's Introduction | Insects, particularly blowflies and their larvae, can provide important evidence in the investigation of a crime. Information about the size and age of blowfly larvae on a corpse can be used to identify the time, and sometimes place, of death. Martin Hall, a forensic entomologist who has worked as an expert witness on over 30 criminal cases, presents a fascinating overview of the ways in which insects can provide vital clues about a murder. Forensic entomology is the interpretation of entomological evidence to help resolve a criminal investigation. Recently, the level of awareness of forensic entomology within the entomological community, especially in the United States, has increased. The insects that have been most extensively studied in relation to their forensic uses are the blowflies--members of the Calliphoridae fly family--in particular their larvae or maggots, because: They are the insects most commonly associated with corpses. They colonise the body most rapidly after death and in greater numbers than most other insect groups. They usually provide the most accurate information regarding the post-mortem interval--the time that has elapsed since death, a major objective in forensic entomology. Blowfly larvae featured in the first successful use of entomological evidence in the UK, when they were discovered on decaying human remains dumped in a small ravine in Dumfriesshire, Scotland, in September 1935. The remains were later identified as those of the wife and maid of Dr Buck Ruxton of Lancaster. The maggots were aged by Dr A.G. Mearns and provided a vital clue as to when the murders took place. Dr Ruxton was subsequently found guilty of the murders and hanged. While the ageing of maggots on corpses represents the most common application of forensic entomology, insects can also be used to assist in many other types of forensic investigation. In another case, an accurate knowledge of the distributions of insects found on cannabis plants imported into New Zealand was used to determine the geographical origin of the plants. Adult blowflies have a finely tuned sense of smell and are attracted in large numbers by the odours of decay, often within a few hours of death. The odours that attract them are mainly created by the action of bacteria on dead tissues. They sometimes swarm to wounds or open sores and ulcers on living vertebrates including humans--the action of larvae feeding on living people causes a disease condition known as myiasis. Entomologists use precise methods to collect and present the evidence correctly--a vital precursor to accurate interpretation. They determine facts about the location of the body and its accessibility to flies at the scene of the crime. The largest and therefore oldest maggots are the most important specimens but the complete range of maggots present will be sampled because they may shed light on different aspects of the investigation. If the entomologist cannot be present at the scene of the crime, the maggots will be collected by crime officers or pathologists who need to provide accurate